Methods

Under an IACUC-approved protocol, the implant was inserted into the right tibia of 16-week-old female C57BL/6 mice (N = 38). The mice were then randomized into 2 groups: Control group (N=19) and Anti-VEGFR group (N=19). A cocktail of VEGFR-1 antibody (25mg/kg) and VEGFR-2 antibody (25mg/kg) was given to the mice in the Anti-VEGFR group by intraperitoneal injection every third day starting immediately after surgery until euthanasia. An equivalent amount of an isotype control antibody was given to the control group. Flow cytometric (N = 4/group) and immunofluorescencent (N = 3/group) analyses were performed at 2 weeks post-implantation to detect the distribution and density of CD31^hiEMCN^hi endothelium in the peri-implant bone. Pull-out testing was used at 4 weeks post-implantation to determine the strength of the bone-implant interface.

Methods

Computational models of six knees were virtually implanted with TKAs based on our previously-developed framework. AR and PR were simulated in each of the six models. A Posterior Stabilized implant was utilized. Standard AR and PR cuts and component positioning were simulated with the femoral component aligned parallel to the transepicondylar axis. In both AR and PR models, the distal femoral cut and the proximal tibial cut were perpendicular to the femoral and tibial mechanical axis, respectively. The amount of posterior bone resected with AR knees ranged from 4.2 to 10.8 mm, and with PR knees ranged from 4.2 to 8 mm. Ligament properties were standardized to reflect a balanced knee at full extension. Passive flexion under 500 N of compression was applied and the MCL and LCL forces were predicted. A new measure, the MCL ratio, that incorporated the femoral insertion of the anterior fiber of MCL relative to the posterior and distal femoral cuts was estimated (Fig. 1). A varus/valgus moment of 6 Nm was applied at full extension and 90‖ of flexion, and the corresponding lateral and medial gaps were measured.

Methods

Twenty-seven patients (mean age 64 years, 30% female) undergoing primary TKA consented to participate in this prospective cohort study. All patients received a highly porous tibial baseplate, a metal backed patella and tantalum RSA bone markers. Implant migration was assessed using model-based RSA at 1.5, 3, 6, 12 and 24 months post-operative. Patient reported outcome measures were captured using the same follow-up schedule, and compared to pre-operative measures.

Methods

This is a prospective randomized study of one modular posterior-stabilized total knee arthroplasty by a single surgeon. 265 patients (329 knees) were randomized to receive a standard compression molded liner (SP) or a highly cross-linked (6.5 CGy electron-beam irradiated and remelted) polyethylene liner (XLP). Patients were evaluated clinically using the classic Knee Society scores, LEAS score, presence of a knee effusion, and by standard radiographs for radiolucent lines and osteolytic lesions. The analysis was performed at a mean of 6 years (range, 2–11 years).

Methods

Subjects who had previously participated in RSA migration studies with 2-year follow-up were recruited to return for a long-term follow-up exam, at least 10 years from their surgery. The implants under study included two cemented designs from two manufacturers and one porous metal monoblock cementless design. At the 10-year visit, subjects had supine RSA exams to determine long-term migration as well as a loaded exam (single leg stance) to determine inducible displacement. Differences between cemented and cementless groups were evaluated with the Mann Whitney U test and Spearman's rank correlation coefficients were calculated for early and late migrations. Significance was set at p < 0.05.

Methods

We obtained data from the UK Clinical Research Practice Datalink (CPRD) that contains information on over 11 million patients (7% of the UK population) registered at over 600 general practices. CPRD data was linked to Hospital Episode Statistics, hospital admissions & Patient Reported Outcome Measures (PROMs) data. We collected data on all KAs (n=64,071) performed over a 21-year period (1995 to 2016).

Outcomes assessed included: local & systemic complications (at 6-months post-surgery): infections (wound, respiratory, urinary), heart attack, stroke & transient ischaemic attack, venous thromboembolism, hospital readmissions & GP visits (1-year), analgesic use (1-year), surgical revision (up to 20-years), mortality (90-days and 1-year), & 6-month change from pre-operative scores in Oxford Knee Score (OKS).

Regression modelling is used to describe the association of smoking on outcomes, adjusting for confounding factors.

Methods

Over a 19-year period (1998–2016), 144 patients underwent primary TKA with a preceding diagnosis of ipsilateral lymphedema (Table 1). There were 114 (79%) females, a mean age of 69 years, and mean BMI of 37.1 kg/m2. Mean follow-up was 7-years (range 2–17 years). A blinded analyst completed a 1:2 match of patients with lymphedema to a group of patients without lymphedema undergoing primary TKA for osteoarthritis during the same period. Matching criteria included sex, age, date of surgery, and BMI. Matched controls included 228 (79%) females along with a mean age and BMI of 69 and 36.4 kg/m2. The mean follow-up for the comparison cohort was 8 years (range 2–18 years). There were no significant differences between groups on the evaluated baseline parameters.

Results: Patients with a history of lymphedema were at a significantly increased risk of revision TKA (HR 7.60, P<0.001), reoperation for any cause (HR 2.87, P<0.001), and postoperative infection (HR 6.19, P<0.001). Patients with lymphedema were also at increased risk for periprosthetic fracture (p=0.04) and tibial component loosening (p=0.01). Morbid obesity increased the risk of reoperation (HR 2.11, p=0.02) and trended toward increased risk of revision TKA (HR 2.29, p=0.059) and infection (HR 2.37, p=0.06).

Discussion: Patients with lymphedema are at significantly increased risk of revision, reoperation, and infection following primary TKA. This data highlights the need for appropriate patient counseling in this population and optimization of lymphedema management before and after TKA.

Methods

Test samples were designed to simulate shapes in current instruments, such as mating pegs and holes, threaded screws, and slotted blocks. Each set was produced in biocompatible materials, ABS-M30i, VeroClear (MED610), Ultem1010, and Nylon 12. Each part was laser scanned, and then imaged virtually using a reverse engineering software (GeoMagic). Manual measurements of key dimensions were also made using calipers. The parts were autoclaved using a standardized protocol, 30 minutes at 250° F. All parts were re-scanned and measured to determine any changes in dimensions. To test for strength and abrasion resistance, the slotted blocks were pinned to sawbones model tibias, and an oscillating saw used to cut through the slot. A compact 3D printed tibial cutting guide was then designed which fitted to the proximal tibia and allowed varus-valgus, tibial slope and height adjustments. A small laser attached to the guide projected to a target at the ankle. Tests were made on 20 sawbones, and compared with 20 with a standard metal cutting guide. Digitization was used to measure the angles of the cuts.

Materials and Methods

A total of 19 A-XLPE tibial inserts were retrieved during revision TKA and matched to 18 retrieved XLPE inserts according to the demographics of the patients, with a mean length of implantation of 15 months (1 to 42). The percentage areas of PE damage on the articular surfaces and the modes of damage were measured. The density of crosslinking of the PE and oxidation were measured at loaded and unloaded regions on these surfaces.

Methods

Board certified orthopedic surgeons’ offices in our county were identified by their AAOS active membership. Knee society membership roll was also utilized. Offices were contacted by telephone and presented with a hypothetical patient with end stage knee osteoarthritis searching for specific treatment (stem cells or PRP injections). T-test was used to compare the Dade county board certified orthopedists to knee society members.

Methods

Patients undergoing primary TKA from 2005 to 2014 were identified in the Medicare database. Patients with PD were matched 1:1 to patients with HD and 1:3 with patients who were not receiving either form of dialysis. Multivariate regression analysis was performed to examine several adverse events including the incidence of infection at 1 year and readmission to the hospital at 30 days.

Methods

The study was designed as a prospective, randomized controlled trial of 50 patients, with 25 patients each in the PSI and CI groups, powered for radiostereometric analysis (RSA). Patients in the PSI group received an MRI and standing 3-foot x-rays to construct patient-specific cut-through surgical guides for the femur and tibia with a mechanical limb alignment. All patients received the same posterior-stabilized implant with marker beads inserted in the bone around the implants to enable RSA imaging. Patients underwent supine RSA exams at multiple time points (two and six weeks, three and six months, and one and two years). At 2 years post-op, a series of RSA radiographs were acquired at different knee flexion angles, ranging in 20° increments from 0° to 120°, to measure the tibiofemoral contact kinematics. Migrations of the femoral and tibial components were calculated using model-based RSA software. Kinematics were measured for each condyle for magnitude of excursion, contact location, and stability.

Methods

Biomechanical testing was performed on six fresh frozen cadaveric knees implanted with a posterior stabilized RP TKA using a gap balancing technique. Rotational displacement and torque were measured over time, while stiffness, yield torque, max torque and displacement were calculated using a post-processing, custom MatLab code. Revision with varying size femoral components (size 3–6) and PE insert thicknesses (10–15mm), by downsizing one step, were used to create a spectrum of flexion/extension gap mismatch. Each configuration was subjected to three loaded testing conditions (0°, 30° and 60° flexion) in balanced and eccentric varus loading, known to represent daily clinical function and “at risk” circumstances.

Methods

We retrospectively reviewed consecutive series of primary TKA from January 2017 to July 2017 and primary UKA from January 2016 to July 2017 using standardized perioperative pain protocols. All patients that underwent any other procedure 6 months prior to and after index surgery were excluded, resulting in 740 TKA and 241 UKA. Demographic and comorbidity information was collected for all patients. Opioid prescriptions, morphine milligram equivalents (MME), sedatives, benzodiazepines, and stimulants were collected from State Controlled Substance Monitoring website 6 months prior and after index procedures. Univariate and multivariate analysis were performed for patients that had a second prescription and continued use (defined as more than 6 months postoperatively).

Methods

Institutional Review Board approval was obtained. A retrospective chart review was performed for all patients with severe arthritis who underwent total hip and knee arthroplasty (THA and TKA) at our institution during the calendar years 2012 and 2017. Patients were excluded if TJA was performed for acute trauma or if no pre-operative UTox screen was obtained. The UTox screen was used to determine preoperative cannabis and opioid use. Chi-squared testing was performed, and significance was defined as p<=0.05.

Methods

A retrospective charge review was performed to identify a cohort of patients who had a primary TKA performed between 2015 and 2016 and later received a CSI. All TKAs and CSIs were performed by a fellowship-trained arthroplasty surgeon. Patients receiving a CSI underwent a clinical exam, laboratory analysis to rule out infection, and radiographic evaluation prior to injection. Patient variables were recorded and a survey assessed the efficacy of the injection. The survey response rate was 63.6%.

Methods

A total of 500 patients from 11 clinics in 6 countries were enrolled into a prospective, multicenter study. All patients were indicated for primary TKA for OA and received components from a single manufacturer. All liners were made from vitamin-E stabilized, highly crosslinked (95 kGy) polyethylene; 54.7% were posterior stabilized (PS) and the remaining were cruciate-retaining.

The Knee Injury and Osteoarthritis Outcome Score (KOOS) was administered at the one-year follow-up visit. The KOOS pain and activities in daily life (ADL) sub-scores were dichotomized and served as the primary outcomes. Dichotomization was done with the patient acceptable symptom state (PASS), defined by previous studies as the value of the PROM above which patients deem their state as acceptable (84.5 points for KOOS pain and 83.0 points for KOOS ADL).

Plain lateral radiographs were taken and assessed for PTS (Figure 1) and PCO (Figure 2). PTS was categorized as above (excessive flexion), within (ideal), or below (extension) the safe zone of 0° − 7° of flexion. PCO increases or decreases of greater than 3mm were compared against no change (≤ 3mm). Each of the two sagittal positioning metrics was tested against the KOOS pain and ADL PASS at one year.

Methods

This is a register study. During 1999–2012, 32,429 cemented, CR TKA's of a specific brand were reported to the Swedish Knee Arthroplasty Register (SKAR). The part numbers for the femur, tibia and insert (in modular implants) were available in 99.2% of cases. The most common combination used the cemented CR femur against a cemented stemmed baseplate in 50.3% of cases while the same CR femur was used against a cemented pegged baseplate in 8.3% of cases, mainly at two hospitals. In order to make the material more comparable, only patients having osteoarthritis (OA) were included and only TKAs using two types of regular constraint inserts and in which the patella had been left un-resurfaced. Chi-Square test was used to investigate gender distribution in the groups and t-test for the mean age at surgery. Kaplan Meier analysis and the log-rank test were used to evaluate the risk of revision until the end of 2016. A p-value <0.05 was considered statistically significant.

Methods

We reviewed our institutional database to identify all patients whom underwent a TKA with a posterior stabilized OxZr femoral component with a minimum of 10 years of follow-up. These were then matched to patients whom underwent a TKA with the identical design posterior stabilized CoCr femoral component during the same time period by gender, age and BMI. All patients had their patella resurfaced. All patients were prospectively evaluated preoperatively and postoperatively at 6 weeks, 3 months, 12 months, 2 years and every 1 to 2 years thereafter. Prospectively collected clinical outcome measures included, Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Short-Form 12 (SF-12) and Knee Society clinical rating scores (KSCRS). Charts and radiographs were reviewed to determine the revision rates and survivorship (both all cause and aseptic) at 10 years allowing comparison between the two cohorts. Paired analysis was performed to determine if differences existed in patient reported outcomes.

Methods

This was an IRB approved, prospectively collected case series, level 4 study. We evaluated 115 patients. 58 patients who had ACI for the treatment of symptomatic bipolar chondral lesions in the PF compartment and 57 in the TF compartment with a minimum 2-year follow up. A single surgeon performed all the surgeries between October 1995 and June 2014. In the PF group, all 58 patients (60 knees; mean age, 36.6 years) were included, and for the TF group one patient did not return for follow-up, 56 patients (58 knees) were included.

For the PF group, an average size of the patella and trochlea lesions were 5.6 ± 2.7 cm2 and 4.2 ± 2.8 cm2, respectively. For the TF group, an average of 3.1 lesions per knee were treated, representing a total surface area of 16.1 cm2 (range, 3.2 – 44.5 cm2) per knee. Patients were evaluated with the modified Cincinnati Knee Rating Scale, Visual Analogue Scale, Western Ontario and McMaster Universities Osteoarthritis Index, and the Short Form 36. Patients also answered questions regarding self-rated knee function and satisfaction with the procedure. Standard radiographs were evaluated for progression of OA.

Methods

The TKA cost calculation included the cost of operative time, implants, cement and cementing accessories. The difference in operative time between cemented and cementless TKA was determined from a previously published study of 100 TKAs performed using a cemented (55) or press fit (45) implant of the same design performed at a single institution by four fellowship trained arthroplasty surgeons. The decision to use cemented or cementless design in these patients was made based on patient bone quality intraoperatively. Operative time was compared between groups using a Student's two-tailed T-test. The cost of operating room time was based on estimates in the recent literature. The cost of cement and cementing accessories was estimated based on publically available market data. The cost of implants was estimated from institutional data for multiple companies.

Methods

All primary TKA performed from 2007–2017 by the two participating surgeons for each of the 3 groups of interest were identified: team SA (N=42 patients; 84 knees), single-surgeon SA (N=146 patients; 292 knees), single-surgeon TA (N=242 patients; 484 knees). No patients were lost to follow-up.

Materials and Methods

We retrospectively reviewed 1194 primary TKA performed for the diagnosis of primary knee osteoarthritis performed at our institution between 2013–2016. There were 291 TKA performed in patients under age 55. Patients were excluded if they had 1) prior history of fracture, 2) renal disease, 3) inflammatory joint disease, and 4) required therapeutic anticoagulation. The primary outcome of interest was rate of revision at 30 days, 1, 2, and 5-year time points. Secondary outcomes included postoperative transfusion rate, calculated blood loss, length of stay(LOS), rate of DVT/PE, readmission and reoperation.

Methods

After receiving an exemption from the Institutional Review Board, we queried our institutional data warehouse for all patients (n=412) that underwent total joint arthroplasty (TJA) of the hip (n=192), knee (n=207), or ankle (n=13), and qualified for our institution's bundled payments model during the study time period (July 2015 – May 2017). Patients with medical conditions that were not well controlled or were potentially optimizable were all sent for preoperative medical optimization prior to surgery. For each 90-day episode, patient characteristics, medical comorbidities, perioperative data, and payments from the Centers for Medicare and Medicaid Services (CMS) were obtained. Episodes where Medicare payments exceeded the target payment were considered “busters”. The busters were older, and had higher comorbidity scores (all, p<0.01). Variables were summarized using descriptive statistics and risk ratios were calculated using a modified Poisson regression analysis.

Methods

From 2012 to 2014, 289 patients with morbid obesity and end-stage OA of the hip or knee were prospectively followed. At initial visit, patients were given a packet on risks of TJA in the morbidly obese and referral information to a weight loss clinic. Patients were contacted at 6, 12, 18 and 24 months from initial visit for PROs, and BMI changes. The average age of patients was 56 (26.7–79.1) there were 218 females and 71 males.

Methods

We performed a retrospective observational study using National Joint Registry (NJR) data on 10,836 propensity matched Oxford UKAs (5418 cemented and 5418 cementless) between 2004 and 2015. Logistic regression was utilized to calculate propensity scores to match the cemented and cementless groups for multiple confounders using a one to one ratio. Standardised mean differences were used before and after matching to assess for any covariate imbalances. The outcomes studied were implant survival, reasons for revision and patient survival. The endpoint for implant survival was revision surgery (any component removal or exchange). Cumulative patient and implant survival rates were determined using the Kaplan-Meier method. Patients not undergoing revision or death were censored on the study end date. The study endpoints implant and patient survival were compared between cemented and cementless groups using Cox regression models with a robust variance estimator.

Methods

Between 2013 and 2016, 349 patients (381 knees) underwent robotic assisted fixed bearing metal backed medial UKAs at two centres. Follow-up was performed at 12 months minimum. Pre- and post-operatively, patients were administered Knee Injury and Osteoarthritis Score (KOOS), Forgotten Joint Score 12 (FJS), and Short-Form summary scale (SF-12) surveys. Clinical results for every score were stratified as ‘excellent’, ‘mild’ and ‘insufficient’. Post-operative complications were recorded. Failure mechanisms, reoperations and post-operative knee pain were also assessed. Intra-operative robotic data relative to femoral and tibial component placement in the coronal, sagittal and horizontal plane, as well as femoro-tibial gaps at different knee flexion angles were also collected.

Methods

One hundred thirty-one consecutive manual UKAs performed by a single surgeon using a cemented, fixed bearing implant were radiographically reviewed by an independent reviewer to avoid surgeon bias. Native and tibial implant slope and coronal alignment were measured on pre- and postoperative lateral and anteroposterior radiographs, respectively. Manual targets were set within 2° of native tibial slope and 0 to 2° varus tibial component alignment. Deviations from target were calculated as root mean square (RMS) errors and were compared to robotic-assisted UKA data.

Methods

95 patients undergoing primary unilateral TKA with one of nine arthroplasty surgeons at a single orthopaedic specialty hospital were prospectively enrolled. Daily pain levels and opioid consumption, and quantity and disposal patterns for left over medications were collected for six weeks following surgery using a novel mobile phone text messaging system. This system automatically queried patients twice a day, storing responses on a secure third-party host that investigators monitored and used to generate data reports in real-time.

Methods

4,458 patients who underwent TJA across 8 major academic centers within one healthcare system were analyzed. Patients who scheduled surgery were registered for the online portal by the surgical coordinator. Upon registration, patients opt-in by signing a license agreement, and data is collected on their utilization of the portal including logins, exercise and educational videos watched, messages sent and PROs completed. Age was compared to utilization, opt-in rates, total videos watched, and messages sent. Two separate patient cohorts were identified to distinguish between active and non-active users. Anyone who opted-in and viewed over 5 preoperative videos or had at least 5 preoperative logins were considered active users. Patients’ postoperative KOOS-JR and HOOS-JR score improvements from baseline were compared between the active vs. non-active groups.

Methods

Twenty-nine patients undergoing same-day bilateral TKA were enrolled in a prospective, randomized blinded study. Subjects were randomized to receive a CSD on one lower extremity while the contralateral limb had the use of a subcutaneous drain (SCDRN) without the use of suction. Isometric quadriceps strength was collected as the primary outcome. Secondary outcomes consisted of quadriceps muscle activation, intraarticular effusion measured via ultrasound, lower extremity swelling measured with bioelectrical impendence, lower extremity girth, ROM, and pain. Outcomes were assessed preoperatively and postoperatively at day 2, 2 and 6 weeks and 3 months. Differences in limbs were determined using paired t-tests or Wilcoxon signed rank tests.

Methods

This is a multicenter retrospective review for patient identification, with prospective telephone survey completion for assessment of functional status. All patients from January 2001 to December 2015 with AKA and prior TKA at two academic centers were included for possible survey enrollment. Demographic information and medical comorbidities were collected, in addition to perioperative and post-operative mortality data. A 23-item survey was provided to all available patients and analyzed for patient functional status.

Methods

100 consecutive primary TKA cases performed by a single surgeon using the same surgical approach and implant design were reviewed. The first 50 patients received F+S nerve blocks and the second 50 received ACB+IPACK blocks preoperatively. Both groups also received total intravenous anesthesia (TIVA). Differences in opioid requirements, length of stay (LOS), distance walked, Western Ontario & McMasters University Osteoarthritis Index (WOMAC), Knee Society (KSS) function scores, Visual Analog Scores (VAS) for pain at rest and with activity, and postoperative complications were analyzed. There were no differences in the groups with respect to age, sex or BMI.

Methods

We retrospectively reviewed 95 patients (102 primary TKAs) from 2000–2014 with a history of a TKA or THA PJI in another joint. Mean age was 69 years; mean BMI was 36 kg/m2. 27% high-risk patients were on chronic antibiotic suppression. Mean follow-up was 6 years. We 1:3 matched (to age, sex, BMI, and surgical year) these to 306 primary TKAs performed in patients with a THA or TKA of another joint without a subsequent PJI. Competing risk with death was used for statistical analysis. Multivariate analysis was utilized to evaluate risk factors for PJI in the study cohort.

Methods

Between October 2012 and June 2017, all patients with painful TKA or THA, who underwent joint aspiration before revision arthroplasty were included in this retrospective study. From aspirated synovial fluid, leukocyte esterase activity, leukocyte CC and PMN% were determined, and specimens were sent for bacterial culture. A total of 524 preoperative joint aspirations (255 hips, 269 knees) were enrolled for final analysis. For 337 patients, the synovial CC and PMN% could be measured by the laboratory. From those patients, 203 patients were scheduled for aseptic revision, and 134 patients for septic revision arthroplasty according to the MSIS criteria for PJI. Specificity (SP), sensitivity (SE), positive predictive value (PPV), negative predictive and overall accuracy were measured for CC and PMN%. The optimum cut-off value was calculated by the ROC and the value giving the AUC, achieving the best possible level of sensitivity and specificity.

Methods

This study was a retrospective, multi-center, radiographic analysis of 1675 consecutive primary uncomplicated TKAs from seven surgeons at three academic and state-funded centers in the US and UK. Surgeons were categorized as “high-volume” (≥50 TKAs/year) and “high-experience” (≥5 years post-fellowship). Femorotibial, tibial varus/valgus, and posterior tibial slope angles were digitally measured using postoperative radiographs. Femorotibial (<2° or >8° valgus), tibial (> ±3° deviation from the neutral axis), and tibial slope (<0° or >7° of flexion for cruciate retaining, <0° or >5° of flexion for posterior stabilized) angle outliers were identified. The proportion of outliers among surgeons in each subgroup was compared.

Methods

Consecutive 115 knees for the diagnosis of osteoarthritis were included in the current study. TKA was performed using posterior cruciate ligament sacrificed prosthesis. A total of 17 men and 96 women with an average age of 75.3 years were included at the time of the surgery. Computed tomography (CT) was taken after TKA in full extension. Postoperative TT-TG distance was measured as a reference of surgical epicondylar axis (SEA) of the femur. Patellar tilt was defined as the angle of the patellar component relative to SEA. Femoral and tibial component rotation was measured as the angle relative to SEA and tibial antero-posterior (AP) axis. Tibial AP axis was defined as the line connecting medial one-third of the tibial tuberosity and center of medial-lateral width. Pearson correlation coefficients were calculated to determine the correlations between patellar tilt and TT-TG distance and between patellar tilt and femoral and tibial component rotation.

Methods

Rotational alignment of 70 TKA patients were evaluated by 3 independent observers using the Berger, and Mayo protocols, which have been previously described, and a new CTTT protocol (Figure 1). The inter and intra-rater interclass correlation coefficients (ICC's), mean difference between measurements and the mean measurement times were calculated. Linear regression analysis was performed to give a coefficient of determination (R2).

Materials and Methods

The clinical outcomes of 133 patients (266 knees) who underwent bilateral TKA between 2013 and 2016 were reviewed. The procedures were performed by three separate surgeons across three major academic institutions. ASA scores, tourniquet time, operative time, blood loss, length of stay, readmission, and postoperative complications were compared between different BMI categories of less than 30 kg/ m2, 30–34.99 kg/ m2, 35–39.99 kg/ m2and above 40 kg/ m2

Methods

We used nation-wide linked discharge data from the Hospital Cost and Utilization Project from 2005–2014 comparing outcomes of simultaneous-bilateral and staged-bilateral total knee arthroplasties (TKAs). Hierarchical logistic regression analysis was used to compare mortality within 30 days, 90 days and 1 year, perioperative risks within 30–60 days, and infection and mechanical complications within 1 year.

Methods

A retrospective review identified 205 lateral unicompartmental arthroplasty procedures performed in two practices over a six-year period (Aug 2011 – June 2017). Patients indicated for surgery met specific preoperative clinical and radiographic criteria confirming lateral compartment arthritic disease with a correctable deformity, intact full-thickness medial cartilage, competent anterior cruciate ligament, and minimal disease in the patellofemoral compartment. A single cemented fixed bearing tibial component design was used in all cases specifically designed for lateral compartment anatomy.

Methods

Patients were enrolled between June 1st, 2016 and March 31st, 2018 in a prospective, non-randomized, open-label, multicenter, consecutive comparative cohort study comparing RTKA and CTKA. Only patients who satisfied the following inclusion criteria were included: body mass index (BMI) ≤ 40kg/m2, primary unilateral TKA procedure, at least 18 years of age, and no joint infection. The following data were collected for analysis:

Preoperative data on component size prediction from CT scans

Methods

We performed a retrospective study of 27 well-fixed, aseptic primary TKAs with persistent pain and/or stiffness, revised by a single, experienced surgeon for suspected metal allergy to nickel based on a positive LTT. Periprosthetic tissue samples obtained at the time of revision surgery were scored using the aseptic lymphocytic vasculitis-associated lesion (ALVAL) scoring system.

Patients and Methods

A total of 167 patients (190 knees with 23 bilateral cases), were recruited prospectively and randomly assigned, with 91 knees receiving the RP and 99 knees receiving FB. The mean age was 65.5 years (48 to 82), the mean body mass index (BMI) was 29.7 kg/m² (20 to 52) and 73 patients were female. The Knee Society Score (KSS), Knee Society Functional Score (KSFS), Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 12-Item Short-Form Health Survey Physical and Mental Component Scores (SF-12 PCS, SF-12 MCS) were gathered and recorded preoperatively, at five-years’ follow-up, and at ten years’ follow-up. Additionally, Knee Injury and Osteoarthritis Outcome Scores (KOOS) were collected at five- and ten-year follow-ups. The prevalence of radiolucent lines (RL) on radiographs and implant survival were recorded at five- and ten-year follow-ups.

Methods

134 patients scheduled for primary unilateral TKA secondary to moderate to severe osteoarthritis were enrolled in this two-institution prospective study. All patient demographics were collected and recorded in an electronic data registry. In addition, patient reported outcome (PRO) questionnaires, including the Knee Injury and Osteoarthritis Outcome Score (KOOS), HSS Patient Expectation Questionnaire, Social Support Survey, Pain Catastrophizing Scale, Visual Analogue Pain Scale (VAS), Geriatric Depression Scale and European Quality (EQ) of Life 5-Dimensions with EQ VAS were prospectively collected at 4 time points (baseline, 4–8 weeks, 9–14 months, 20–26 months postoperative). Statistical analysis was then conducted among patients of different gender and ethnic background to assess for the effect of these demographic variables on patient expectations and outcomes.

Methods

Patients 18 years and older undergoing TKA between the years of 2005 and 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP). Patients whose length of stay (LOS) was >4 days were excluded. Patient demographics, anesthesia type, length of operation and hospital stay, as well as 30-day major and minor complications were collected from the database. Chi square tests were utilized to compare the unadjusted rates of complications between patients whose LOS was 0, 1, 2, and 3–4 days. Multivariable regression was utilized to evaluate the effect of LOS on complication rates, while adjusting for age, American Society of Anesthesiologist (ASA) class, type of anaesthesia, functional status, comorbidities, sex, steroid/immunosuppressant use, body mass index (BMI), diabetes, length of operation and smoking status.

Materials and Methods

Our study group consisted of 64 consecutive non infected RTKR patients who underwent a revision of the polyethylene alone between 1998 and 2006. All patients had been treated originally with the same cemented, CR, patella resurfaced primary TKR. Reasons for revision were 51 poly wear and/or osteolysis, 7 instability, and 6 other. The average time from the primary to the revision surgery was 9.1 years (range 2.2 to 16.1 years). All patients had an isolated poly liner change. No femurs or tibial trays were revised. Average age of the cohort at revision was 72.2 (range 48 to 88). Average BMI was 31.9 (range 23.6 to 43.9). There were 36 female patients. Of the group, 42 were ASA 1 or 2 and 22 were ASA 3. Pre-op alignment averaged 6.0 (range 2 varus to 8 valgus). Patients were followed for a minimum of 10 years (range 10 to 19 years).

Materials and Methods

An FDA prospective study under investigational device exemption was conducted from 2017–2018. Pre-operative CT scans were used to create a pre-operative plan using the TSolution One? Surgical System (THINK Surgical, Inc). TKA was performed using a standard approach, with planned and robotically executed femoral and tibial resections. Subjects completed 3-month follow-up with post-operative CT scans. A validated method was used to compare pre- and post-operative CT scans to determine differences between planned and achieved implant position. Femoral and tibial component sizing, and mean differences in implant position and alignment were compared. Short Form 12 Physical (PCS) and Mental Component Summary (MCS) scores as well as Knee Society (Objective and Functional) scores at 12 weeks post-operatively were compared with pre-operative scores. Paired-sample t-tests were used for comparisons.

Methods

In a randomized-controlled fashion, patients underwent primary TKA soft tissue balancing either free-hand or with VERASENSE (Orthosensor Inc, Dania FL) at our institution beginning January 2018. With VERASENSE, soft-tissue balancing is considered when the pressure difference between the medial and lateral knee compartments was less than 15 pounds. Data regarding patient-reported outcomes, knee range of motion (ROM), pain level, opioid consumption, inpatient ambulation distance, length of stay (LOS), and incidence of arthrofibrosis was collected and analyzed in a two-year minimum follow-up and target patient goal of 120 patients.

Methods

Ninety-day clinical and economic outcomes for 252 patients with prospectively collected data from the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) database were reviewed. Ninety-day outcomes were compared between uncemented knees and an age-matched group of cemented knees (Triathlon cemented vs uncemented Triathalon-tritanium, Stryker Orthopedics, Mahwah, NJ, USA). Both cruciate retaining and posterior stabilized designs were included. MARCQI data: demographics, co-morbidities, length of stay, complications, emergency department visits, discharge disposition, and readmissions were reviewed. Financial data provided by the hospital's finance department was used for economic comparisons. Fischer's test was done to assess categorical data and a student's t-test was used to compare numerical data.

Methods

Using our institution's total joint arthroplasty registry, we identified 4,135 patients who underwent total knee replacement (TKR) using one of the five most common implant brands used at our institution. These included Biomet Vanguard (N=211 patients), Depuy/Johnson&Johnson Sigma (N=221), Exactech OptetrakLogic (N=1,507), Smith & Nephew Genesis II (N=1,414), and Zimmer NexGen (N=779). Only posterior-stabilized primary TKRs in patients with osteoarthritis were included. Patients were evaluated preoperatively using the Knee Osteoarthritis Outcomes Score (KOOS), Lower Extremity Activity Scale (LEAS), and Short Form-12 (SF-12). Demographics including age, body mass index (BMI), Charleston Comorbidity Index (CCI), ASA physical status classification, sex, and smoking status were collected. Postoperatively, 2-year KOOS, LEAS, SF-12, and satisfaction scores were compared between implant groups.

Methods

Our institutional database was utilized to retrospectively identify a cohort of consecutive patients from January 2014-January 2018 who had undergone unilateral primary TKA with a single surgeon utilizing a preoperative single-shot ACB in addition to a standardized multimodal pain regimen versus those that only received the same multimodal pain regimen (no-ACB). The primary reason that a patient did not receive a preoperative block was lack of availability of the block team The time period of interest was selected based on the implementation of our current pain protocols. The multimodal pain regimen consists of: preoperative Tylenol, a periarticular injection intraoperatively including 0.5% Marcaine and Toradol, IV Toradol postoperatively, Percocet, Celebrex and IV narcotic medication for breakthrough pain. These 2 groups were compared utilizing independent sample T-tests with primary endpoints of interest being LOS (in total hours and as %day 1 discharges (%POD1)), distance ambulated with inpatient therapy on postoperative day 1, and inpatient narcotic use as measured in morphine equivalents per hour. A sub-cohort of patients with adductor canal block was then selected based on time of surgery to control for time of discharge and hours in the hospital to isolate the effect of the block.

Methods

rTKAs for PJI from 2005–2016 were reviewed. Extensive hardware was defined as: metaphyseal cone/sleeve fixation, distal femoral replacement, periprosthetic fracture hardware, or stems >75mm. Cases were categorized by treatment (I&D or 2-stage exchange).

Methods

TKA procedures were identified using the Medicare 100% Standard Analytic Files including; Inpatient, Outpatient, Skilled Nursing (SNF) and Home Health. Members included patients with rTKA or manual TKA (mTKA) between 1/1/2016-3/31/2017. To account for potential baseline differences, propensity score matching (PSM) was performed in a 1-to-5 ratio, robotic to manual based on age, sex, race, geographic division, and comorbidities. After PSM, 519 rTKA and 2,595 mTKA were identified and included for analysis. Ninety-day episode-of-care cost, index cost, LOS, discharge disposition and readmission rates were assessed.

Methods

The Yale Center for Musculoskeletal Care and Baker Tilly Healthcare Management reviewed episode expenditures among Medicare beneficiaries who received CIM and OTS implants for TKA between 01/01/2015 and 12/31/2015. Episode costs included the pre-operative CT scan, index TKA procedure, and 12-month post-index spending for inpatient (IP), outpatient (OP), emergency room (ER), skilled nursing facility (SNF), and home health (HH) services. CIM patients were identified through a matching process utilizing de-identified patient demographic and procedural information and the presence of a CT scan 28–365 days before index. OTS patients included those without a CT scan within one year of index. CIM and OTS cohorts were propensity matched to produce comparable cohorts at a one-to-five ratio based on age range, gender, race, geographical location, and comorbidities. Average expenditure was used to calculate one-year costs of care differences between the CIM and the OTS technologies. A Generalized Linear Model (GLM) and two-part model (logistics and GLM) were used to test statistical significance.

Methods

Findings of 1263 consecutive patients undergoing revision knee surgery, at a high-volume referral center, were reviewed. 161 cases of active infection were excluded. Complete histopathology reports were subsequently available for 321 (29.1%) non-infective cases. Each case was independently histologically-classified using a previously validated scoring system reflecting ALVAL grade. Post-operative patient-reported outcomes measures (PROMs) were available for 134 patients (41.7%), allowing direct correlation between functional performance and the established histopathology results.

Methods

Motion and electromyography (EMG) data were collected during level walking and stair climbing for 16 BiCR subjects (4/12 m/f, 65±3 years, 30.7±7.0 BMI, 8/8 R/L), 17 PCR subjects (2/15 m/f, 65±7 years, 30.4±5.1 BMI, 7/10 R/L), and 17 elderly healthy control subjects (8/9 m/f, 55±10 years, 25.8±4.0 BMI, 10/7 R/L), using the point cluster marker set. Surface EMG electrodes were placed on the vastus medialis obliquus (VMO), rectus femoris (RF), biceps femoris (BF), and semitendinosus (ST) muscles. EMG data are reported as percent relative voluntary contraction (%RVC), normalized to the average peak EMG signals during level walking. Statistical nonparametric mapping was used for waveform analysis.

Methods

From October 2011-March 2015, 19 sites prospectively enrolled and implanted 752 Subjects with Existing TKA. Between November 2012 and May 2015, 23 sites (18 sites had enrolled Existing TKAs), implanted 1131 Subjects with the New TKA. Demographics were similar between groups. Subjects were seen preoperatively, <1-year, 1-year, and 2-years to collect patient reported outcome measures (PROMs), radiographs and any complications. PROMs consisted of Knee Injury and Osteoarthritis Outcome Score (KOOS) (permits WOMAC scoring), Oxford Knee Score (OKS), Patient's Knee Implant Performance (PKIP) and EQ5D-3L and a p-value of 0.01 was established for statistical significance for PROMs comparisons. Kaplan-Meier (KM) implant survivorship (revision of any component for any reason) estimates were calculated.

Methods

All patients with history of ACL or MLK reconstruction who underwent TKA between 2007–2018 were identified in a single institution registry. A matched cohort was identified based on patient age, body mass index (BMI), sex, and year of surgery. The primary outcome measure was utilization of constrained implants. Secondary outcomes included rates of deep vein thrombosis (DVT), pulmonary embolism (PE), infection, postoperative transfusion, postoperative knee range of motion (ROM), revision surgery, and patient reported outcomes (Knee Injury and Osteoarthritis Outcome Score for joint replacement (KOOS, JR).

Introduction

Total knee arthroplasty (TKA) candidates have historically received high doses of opioids within the perioperative period for the management of surgical pain. Healthcare systems have responded by improving opioid prescribing documentation and implementing narcotic-sparing pain protocols into TKA integrated care pathways (ICP). Despite these efforts, there are few technological platforms specifically designed to measure the narcotic burden immediately postoperatively. Here we present an early iteration of an inpatient narcotic administration-reporting tool, which normalizes patient narcotic consumption as an average daily morphine-milligram-equivalence (MME) per surgical encounter (MME/day/encounter) among total knee arthroplasty (TKA) recipients. This information may help orthopaedic surgeons visualize their individual granular inpatient narcotic prescribing habits individually and compared to other surgeons, while taking into consideration patient and procedure specific variables in order to optimize use and curtail unnecessary narcotic prescriptions.

Methods

Look AHEAD is a multicenter, randomized trial which began in August 2001 and follow-up continued for a median of 11.3 years at 16 academic centers. 5145 persons aged 45–76 with diabetes were randomized to either an ILI with reduced calorie consumption and increased physical activity designed or to diabetes support and education intervention (DSE). TKR events were ascertained every 6 months. Retrospective data of reported knee pain was assessed using the WOMAC knee pain questionnaire. Participants with partial TKR or revisions were excluded. Cox proportional hazard models were used to relate baseline BMI category (obese, Class I, Class II, or Class III obesity), baseline knee pain, and treatment group with TKR. Weight change category (lost<=5%, stable, gained>=2%) from baseline to year 1 follow-up by treatment assignment was also examined as a predictor of TKR after excluding TKR occurring prior to year 1.

Methods

233 Septic and aseptic revision TKA from six-centers were randomized to either receive 1g pre-incision intravenous (IV) TXA, 1g pre- and post-incision IV TXA, 1g pre-incision IV and 1g intra-operative topical TXA, or three doses of 1950mg oral TXA given 2 hours pre-operatively, 6 hours post-operatively, and the morning of postoperative day 1. Randomization was performed based on type of revision to ensure equivalent distribution among groups. The primary outcome was reduction in hemoglobin. Power analysis determined 40 patients per group were necessary to identify a 1g/dL difference with an alpha of 0.05 and beta of 0.80. Per-protocol analysis involved regression analysis and two one-sided t-tests for equivalence.

Methods

We developed an online survey instrument consisting of 69 items encompassing pre-operative, intraoperative, and post-operative tasks that preliminary studies identified as the essential components of revision TKR. These tasks encompassed 4 domains: clinical decision-making skills (n=9), interpersonal assessment and communication (n=7), surgical decision-making (n=35) and procedural surgical tasks (n=18). Respondents rated the difficulty of each item on a 5-level Likert scale, with an ordinal score ranging from 1 (“very easy”) to 5 (“very difficult”. The survey instrument was administered to a cohort of 109 US surgeons: 31 trainees enrolled in a joint fellowship program (Fellows) and 78 surgeons who had graduated from a joint fellowship program within the previous 10 years (Joint Surgeons). Using appropriate parametric and non-parametric tests, the responses were analyzed to examine the variation of reported difficulty of each of the 69 items, in addition to the nature of the task (cognitive, surgical, clinical and interpersonal), and differences between Fellows and Surgeons.

Methods

The PearlDiver national insurance database was queried from 2007–2015 for all patients who underwent primary TKA. Kaplan-Meier Curve survival analysis and log rank test were performed to evaluate revision rates between age groups (<40, 40–49, 50–59, 60–69, 70–79, 80–89, and ≥90 years). Complication rates were compared to rates in the age 60–79 group using multiple logistic regressions controlling for baseline demographics and comorbidities.

Methods

We enrolled 181 patients (222 knees), who had primary TKA performed by the same surgeon at Lilavati Hospital & Research Centre, Mumbai, between June 2016 to February 2017. NKSS was administered to each patient preoperatively. At 1 year, they were prospectively called for review and NKSS and FJS were administered. 151 patients attended the review clinic and 17 patients completed the forms with the help of their physiotherapist and sent them via email. 13 patients who could not do either, were excluded from the study. Thus, we had 168 patients (207 knees) whose complete data was analyzed. Of 168 patients, 37 were males and 131 were females, with an average age of 67 years (37–85). Patients were divided into two groups based on their FJS score - Group A (FJS<50) and Group B (FJS≥50). The demographics and NKSS in both groups were compared. The study was approved by our Institutional Review Board.

Statistical analysis was done using SPSS software. Raw data statistics for FJS was determined and unpaired t-test used to compare all parameters in Groups A and B. Correlation of NKSS to FJS was analyzed using Pearson's correlation test.

Method

We recruited consecutive patients with osteoarthritis and randomized them to either standard patient education (n=207), or to our standard patient education plus a new e-learning tool (n=209). Preoperative measures were completed following the patients’ Pre-Admission clinic (PAC) visit and prior to accessing the e-learning tool. Postoperative patient reported outcome measures (PROMs) were completed at six weeks, three months and one year after TKA.

We used the Postoperative Expectation Questionnaire to measure the degree to which patient expectations had been met and the Patient Acceptable Symptom State (PASS) question to measure patient satisfaction at one year postoperative. We collected several PROMs for descriptive purposes including: new Knee Society Knee Scoring System (KSS); (Pre-Op and Post-Op versions), Knee injury and Osteoarthritis Outcome Score (KOOS), the Medical Outcomes Study 12-Item Short Form Health Survey, version 2 (SF-12), Hospital Anxiety and Depression Scale (HADS), Pain Catastrophizing Scale (PCS), University of California at Los Angeles (UCLA) Activity Score, and the Social Role Participation Questionnaire (SRPQ).

Methods

Patients undergoing TKA between 2005 and 2015 were identified using the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database. Patients were stratified based on preoperative hypoalbuminemia (<3.5 g/dL) and ASA score (≤ 2 vs. > 2). Multivariable regression analysis adjusted for age, sex, BMI, and smoking status was utilized to determine predictive potential of hypoalbuminemia and ASA score on each postoperative complication.

Background

The Bundled Payments for Care Improvement (BPCI) initiative was introduced to reduce healthcare costs while maintaining quality. We examined data from a healthcare system comprised of five hospitals that elected to participate in the BPCI Major Joint Replacement of the Lower Extremity Model 2 initiative beginning July 1, 2015. We compared one hospital that did 507 BPCI knee cases to the four other hospitals that did 566 cases. Stratifying the data by hospital volume, we sought to determine if costs decreased during the BPCI period, how the savings were achieved, and if savings resulted in financial rewards for participation.

Methods

The Medicare data included the target cost for each episode (based on historical data from 2009–2012 for each hospital that was adjusted quarterly) and actual Part A and Part B spending for 90 days. Using 1,836 primary knee replacements, we analyzed the costs associated with the anchor hospitalization, inpatient rehabilitation, skilled nursing facilities, home health, outpatient physical therapy and readmission to compare the 1,073 knees done during the 16-month BPCI initiative period with the 763 knees done during the 1-year period preceding BPCI participation. Owing to the nonparametric distribution of the cost data, a Mann-Whitney U test was used to compare the higher volume hospital with the four lower volume hospitals.

Methods

The Centers for Medicare & Medicaid Services (CMS) received PRO data voluntarily submitted by hospitals in a bundled payment model for THA/TKA procedures. Participating hospitals who collected and successfully submitted these data received an increase in their overall quality score, possibly resulting in a positive impact on model reconciliation payments. PRO data were collected from Medicare Fee-For-Service beneficiaries >= 65 years undergoing elective primary THA/TKA procedures from July 1 to August 31, 2016 at hospitals participating in the model. Pre-operative PRO and risk variable data were collected 0 – 90 days prior to surgery, while post-operative PRO data were collected 270 – 365 days following elective THA/TKA. PRO pre-op and post-op data were matched to Medicare claims data for determination of clinically eligible procedures and clinical comorbidities. We compared the characteristics of patients submitting PRO data to other elective primary THA/TKA recipients in the US.

Methods

A novel cross-sectional study was designed. Revised medial meniscal bearing UKR with primary operation registered with the NJR between 2006 and 2010 were identified. Participating centres from all over the country provided blinded pre-operative, post-operative, and pre-revision radiographs. Two observers reviewed the radiographs.

Patients and Methods

A total of 558 Avon PFJ arthroplasties in 431 patients, with minimum two-year follow-up, were identified from a prospective database. Patient-reported outcomes and implant survivorship were analyzed, with follow-up of up to 18 years.

Methods

This cross-sectional study compared three different study populations: 32 patellofemoral pain subjects (mean age, 32 years (22 to 45); 72% female); 56 isolated radiological patellofemoral osteoarthritis subjects (mean age, 54 years (44 to 58); 89% female); and 80 healthy control subjects (mean age, 52 years (44 to 58); 74% female). Measurements included questionnaires, and lateral and skyline radiographs of the knee. Two separate 30-point 2D statistical shape models of the patella were created from the lateral and skyline radiographs. A general linear model was used to test for differences in standardized shape modes (a specific shape variant of the patella) between patellofemoral osteoarthritis, patellofemoral pain, and controls, using Bonferroni correction and adjustment for body mass index and gender.

Patients and Methods

In this randomized controlled trial, 200 patients were randomized to receive a single dose of 2.0 g of TXA orally two hours preoperatively (group A), a single dose of TXA followed by 1.0 g orally three hours postoperatively (group B), a single dose of TXA followed by 1.0 g three and nine hours postoperatively (group C), or a single dose of TXA followed by 1.0 g orally three, nine, and 15 hours postoperatively (group D). All patients followed a routine enhanced-recovery protocol. The primary outcome measure was the total blood loss. Secondary outcome measures were hidden blood loss (HBL), reduction in the level of haemoglobin, the rate of transfusion and adverse events.

Patients and Methods

This prospective single-surgeon cohort study included 60 consecutive conventional jig-based UKAs compared with 60 consecutive robotic-arm assisted UKAs for medial compartment knee osteoarthritis. Patients undergoing conventional UKA and robotic-arm assisted UKA were well-matched for baseline characteristics including a mean age of 65.5 years (sd 6.8) vs 64.1 years (sd 8.7), (p = 0.31); a mean body mass index of 27.2 kg.m2 (sd 2.7) vs 28.1 kg.m2 (sd 4.5), (p = 0.25); and gender (27 males: 33 females vs 26 males: 34 females, p = 0.85). Surrogate measures of the learning curve were prospectively collected. These included operative times, the Spielberger State-Trait Anxiety Inventory (STAI) questionnaire to assess preoperative stress levels amongst the surgical team, accuracy of implant positioning, limb alignment, and postoperative complications.

Patients and Methods

A total of 240 patients who were enrolled in this randomized controlled trial (RCT) underwent a primary cemented TKA with one of three tibial components (all-polyethylene fixed-bearing, modular metal-backed fixed-bearing and mobile-bearing). Patients were reviewed at a median follow-up of ten years (IQR 9.2 to 10.4).

Patients and Methods

This prospective cohort study included 40 consecutive patients undergoing conventional jig-based TKA followed by 40 consecutive patients receiving robotic-arm assisted TKA. All surgical procedures were performed by a single surgeon using the medial parapatellar approach with identical implant designs and standardized postoperative inpatient rehabilitation. Inpatient functional outcomes and time to hospital discharge were collected in all study patients.

Methods

Anteroposterior radiographs of the knee and bone mineral density (BMD) and T-scores from DXA scans of 361 healthy patients were prospectively analyzed. The mean cortical bone thickness (CBTavg) and the distal femoral cortex index (DFCI) were the two parameters that were proposed and measured. Intra- and interobserver reliabilities were assessed. Correlations between the BMD and T-score and these parameters were investigated and their value in the diagnosis of osteoporosis and osteopenia was evaluated.

Patients and Methods

A retrospective cohort of 2521 patients undergoing a primary unilateral TKA were identified from an established regional arthroplasty database. Patient demographics, comorbidities, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and 12-Item Short-Form Health Survey (SF-12) scores were collected preoperatively and one year postoperatively. Patient satisfaction was assessed using four questions, which focused on overall outcome, activity, work, and pain. Logistic regression analysis was used to identify independent preoperative predictors of increased stiffness when adjusting for confounding variables.

Methods

Anterior cruciate ligament reconstruction using the plantaris tendon as graft material was performed on both knees of 24 rabbits (48 knees) to mimic ACL reconstruction by two different suspensory fixation devices for graft fixation. For the adjustable fixation device model (Socket group; group S), a 5 mm deep socket was created in the lateral femoral condyle (LFC) of the right knee. For the fixed-loop model (Tunnel group; group T), a femoral tunnel penetrating the LFC was created in the left knee. Animals were sacrificed at four and eight weeks after surgery for histological evaluation and biomechanical testing.

Patients and Methods

A total of 126 patients who underwent unilateral TKA in 2006 were prospectively included in this retrospective study. They were categorized into two groups based on BMI: < 30 kg/m² (control) and ≥ 30 kg/m² (obese). Functional outcome was assessed using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS), and Oxford Knee Score (OKS). Quality of life was assessed using the Physical (PCS) and Mental Component Scores (MCS) of the 36-Item Short-Form Health Survey.

Patients and Methods

A total of 45 patients underwent 46 UKAs for knee osteonecrosis between 2002 and 2014 at our institution (The Mayo Clinic, Rochester, Minnesota). Twenty patients (44%) were female; the mean age of the patients was 66 years, and mean body mass index (BMI) was 31 kg/m². Of the 46 UKAs, 44 (96%) were medial UKAs, and 35 (76%) were fixed-bearing design. Mean mechanical axis postoperatively was 1.5° varus (0° to 5° varus); 41 UKAs (89%) were performed for primary osteonecrosis. Mean follow-up was five years (2 to 12)

Patients and Methods

A total of 174 patients who underwent second-look arthroscopic evaluation after anatomical ACL reconstruction were enrolled in this study. The graded condition of the articular cartilage at the time of ACL reconstruction was compared with that at second-look arthroscopy. Age, gender, body mass index (BMI), ACL reconstruction technique, meniscal conditions, and other variables were assessed by regression analysis as risk factors for progression of damage to the articular cartilage.

Materials and Methods

Six cementless OUKR tibial components were implanted in 12 new slots prepared on blocks of solid polyurethane foam (20 pounds per cubic foot (PCF), Sawbones, Malmo, Sweden) with a range of interference of 0.1 mm to 1.9 mm using a Dartec materials testing machine HC10 (Zwick Ltd, Herefordshire, United Kingdom) . The experiment was repeated with cellular polyurethane foam (15 PCF), which is a more porous analogue for trabecular bone.

Patients and Methods

A total of 15 patients from a previously reported prospective trial of fixation using radiostereometric analysis (RSA) were examined at a mean of 11 years (10 to 11) postoperatively. Longitudinal supine RSA examinations were acquired at one week, one year, and two years postoperatively and at final follow-up. Weight-bearing RSA examinations were also undertaken with the operated lower limb in neutral and in maximum internal rotation positions. Maximum total point motion (MTPM) was calculated for the longitudinal and inducible displacement examinations (supine versus standing, standing versus internal rotation, and supine versus standing with internal rotation).

Patients and Methods

A total of 182 patients aged between 45 and 75 years undergoing unilateral TKA at a tertiary centre were randomized to receive TXA, either 1.5 g intra-articularly after closure of the wound (n = 91) or two doses of 10 mg/kg IV (n = 91). The primary outcome measure was the reduction in the level of haemoglobin (Hb) in the blood on the fifth postoperative day. Secondary outcome measures were the total, visible, and hidden blood losses (TBL, VBL, HBL). We assumed equivalence of the primary outcome in both routes with a margin of ± 0.35gm/dl. Block randomization using computer-generated random numbers was used. The patients and the assessor of outcome were blinded.

Materials and Methods

A total of 14 cadaveric tibias were randomized to either a pilot hole (n = 7) or a no-hole (n = 7) condition. Lateral cortex strains were measured while the osteotomy was opened 9 mm and secured in place with a locking plate. The tibias were then subjected to an initial 800 N load that increased by 200 N every 5000 cycles, until failure or a maximum load of 2500 N.

Patients and Methods

A retrospective cohort consisting of 1369 patients undergoing a primary TKA for osteoarthritis that had not undergone revision were identified from an established arthroplasty database. Patient demographics, comorbidities, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and Short Form 12 (SF-12) questionnaire scores were collected preoperatively, and one and five years postoperatively. In addition, patient satisfaction was assessed at one and five years postoperatively. Logistic regression analysis was used to identify independent predictors of satisfaction at one and five years.

Patients and Methods

A single-centre assessor-blinded, comprehensive cohort study, incorporating a pilot randomized controlled trial (RCT) was performed on patients with a symptomatic compartment of the knee in which a (sub)total meniscectomy had previously been performed. They were randomized to be treated either with a meniscal allograft transplantation or personalized physiotherapy, and stratified for malalignment of the limb. They entered the preference groups if they were not willing to be randomized. The Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score and Lysholm score and complications were collected at baseline and at four, eight and 12 months following the interventions.

Patients and Methods

A retrospective, multi-institutional study was conducted on 18 951 patients, 3685 who underwent SBTKA and 15 266 who underwent UTKA, using aspirin or warfarin as VTE prophylaxis. Each patient was assigned an individualised baseline VTE risk score based on a system using the Nationwide Inpatient Sample. Symptomatic VTE, including pulmonary embolism (PE) and deep vein thrombosis (DVT), were identified in the first 90 days post-operatively. Statistical analyses were performed with logistic regression accounting for baseline VTE risk.

Methods

The contact stresses on the polyethylene (PE) insert, articular cartilage and lateral meniscus were evaluated in PS and standard off-the-shelf prostheses for UKA using a validated finite element model. Gait cycle loading was applied to evaluate the biomechanical effect in the PS and standard UKAs.

Patients and Methods

We retrospectively evaluated 363 consecutive, lateral UKAs (346 patients) performed using the Oxford domed lateral prosthesis undertaken in three high-volume knee arthroplasty centres between 2006 and 2014. Mean age of the patients at surgery was 65 years (36 to 88) with a mean final follow-up of 37 months (12 to 93)

Materials and Methods

We identified 4205 patients who had undergone UKA between 2007 and 2015 from the Humana Inc. administrative claims database. Post-operative opioid use for one year post-operatively was assessed using the rates of monthly repeat prescription. These were then compared between patients with and without a specific variable of interest and with those of patients who had undergone TKA and THA.

Methods

We generated a subject-specific computational model followed by the development of ± 1 mm, ± 2 mm and ± 3 mm PCO models in the posterior direction, and -3°, 0°, 3° and 6° PTS models with each of the PCO models. Using a validated finite element (FE) model, we investigated the influence of the changes in PCO and PTS on the contact stress in the patellar button and the forces on the posterior cruciate ligament (PCL), patellar tendon and quadriceps muscles under the deep knee-bend loading conditions.

Materials and Methods

We investigated the in vivo kinematics of eight normal knees in four male volunteers (mean age 41.8 years; 37 to 53) using 2D and 3D registration technique, and modelled the knees with a computer aided design program. Each subject squatted, kneeled, and sat cross-legged. We evaluated the femoral rotation and varus-valgus angle relative to the tibia and anteroposterior translation of the medial and lateral side, using the transepicodylar axis as our femoral reference relative to the perpendicular projection on to the tibial plateau. This method evaluates the femur medially from what has elsewhere been described as the extension facet centre, and differs from the method classically applied.

Patients and Methods

A total of 29 patients at two centres received uncemented PA-coated tibial components and were followed for two years with radiostereometric analysis exams to quantify the migration of the component.

Methods

Validated finite element models for varus and valgus malalignment by 3° and 5° were developed to evaluate the effect of malalignment on the tibial component in TKA. Maximum contact stress and contact area on a polyethylene insert, maximum contact stress on patellar button and the collateral ligament force were investigated.

Patients and Methods

Patients were randomised to PA-coated or cemented TKAs. In 60 patients (30 in each group), radiostereometric analysis of tibial component migration was evaluated as the primary outcome at baseline, three months post-operatively and at one, two and five years. A linear mixed-effects model was used to analyse the repeated measurements.

Patients and Methods

Between 2000 and 2010, 60 patients undergoing aseptic revision TKA for flexion instability were identified. The results of the pre-operative aspiration of synovial fluid were available for 53 patients (88%). These patients were 1:2 matched to 106 patients who underwent aseptic TKA for indications other than flexion instability. The mean age of the patients at revision TKA was 65 years (44 to 82) and 55% were women. The mean follow-up was 4.3 years (2 to 10.2).

Patients and Methods

This study was a retrospective review of data from an institutional arthroplasty registry for cases performed between 2001 and 2014. A total of 292 patients were identified, of which 217 had a revision of HTO to TKA, and 75 had revision of UKA to TKA. While mean follow-up was longer for the HTO group compared with the UKA group, patient demographics (age, body mass index and Charlson co-morbidity index) and PROMs (Short Form-36, Oxford Knee Score, Knee Society Score, both objective and functional) were similar in the two groups prior to revision surgery. Outcomes included the rate of complications and re-operation, PROMS and patient-reported satisfaction at six months and two years post-operatively. We also compared the duration of surgery and the need for revision implants in the two groups.