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Papers by William Mihalko

Orthopedic Clinics of North America

Journal of the American Academy of Orthopaedic Surgeons

Introduction: This study evaluated the effect of bupivacaine versus mepivacaine spinal anesthesia... more Introduction: This study evaluated the effect of bupivacaine versus mepivacaine spinal anesthesia and preoperative adductor canal block (ACB) on recovery, length of stay, pain, and complications of same-day discharge total knee arthroplasty (TKA) at a free-standing ambulatory surgery center. Methods: We performed a retrospective review of patients who underwent TKA between March 2018 and September 2019. The patients were grouped based on the neuraxial anesthetic regimen: bupivacaine with ACB, bupivacaine without ACB, and mepivacaine without ACB. Preoperative ACBs were discontinued in December 2018, and use of mepivacaine spinal anesthesia was initiated in March 2019. Length of stay in the postanesthesia care unit (PACU), time to controlled void and ambulation, postoperative pain, morphine milligram equivalents (MME), and transient neurologic symptoms were compared. Results: Ninety consecutive patients who underwent TKA were identified. Fifty patients received bupivacaine with ACB, 2...

Journal of Bone and Joint Surgery-british Volume, 2017

Introduction Total knee arthroplasty (TKA) is a successful procedure for end stage arthritis of t... more Introduction Total knee arthroplasty (TKA) is a successful procedure for end stage arthritis of the knee that is being performed on an exponential basis year after year. Most surgeons agree that soft tissue balancing of the TKA is a paramount to provide a successful TKA. We utilized a set of retrieved lower extremities with an existing TKA to measure the laxity of the knee in all three planes to see if wear scores of the implants correlated to the laxity measured. This data has never been reported in the literature. Methods IRB approval was obtained for the local retrieval program. Each specimen was retrieved after removing the skin, subcutaneous tissue and muscle from mid thigh to mid tibia. The femur, tibia and fibula were then transversely cut to remove the specimen for testing. Each specimen was then imaged using a flouroscopic imaging unit (OEC, Inc) in the AP, Lateral and sunrise views. These images were used to analyze whether there were any signs of osteolysis. Each specimen...

Journal of Bone and Joint Surgery-british Volume, 2017

Introduction Early hip OA may be attributed to smaller coverage of the femoral head leading to hi... more Introduction Early hip OA may be attributed to smaller coverage of the femoral head leading to higher loads per unit area. We hypothesize that tight hamstrings may contribute to increased loads per unit area on the femoral head during gait. When a patient has tight hamstrings they cannot flex their pelvis in a normal fashion which may result in smaller coverage of the femoral head (Figure 1). This study aimed to determine if subjects with tight hamstrings can improve femoral head coverage during gait after a stretching intervention. Methods Nine healthy subjects with tight hamstrings (popliteal angle>25°) were recruited and consented for this IRB approved study. Gait analysis with 58 reflective markers were placed by palpation on anatomical landmarks of the torso and lower extremities. Ten optoelectronic cameras (Qualisys, Gothenburg, Sweden) and three force plates (AMTI, Watertown, MA) were used to track marker position and measure foot strike forces. Subjects walked at a self-s...

Journal of Bone and Joint Surgery-british Volume, 2017

Introduction Gelsolin (GSN) is a protein whose function in the cytoplasm is to regulate intracell... more Introduction Gelsolin (GSN) is a protein whose function in the cytoplasm is to regulate intracellular actin assembly, while circulating plasma GSN has been implicated in the clearance of cellular byproducts via the body's scavenger system. In knee synovial fluid, GSN appears to be protective of inflammation as lower levels have been found in patients with rheumatoid arthritis while higher levels have been demonstrated in hypersensitivity reactions to metallic implants. The purpose of this study is to define the role of GSN in painful total knee arthroplasty (TKA) patients as a biomarker to distinguish septic from aseptic diagnoses. Methods After Institutional Review Board (IRB) approval, 50 patients were enrolled in the study into two cohorts. 25 patients presented with a painful TKA and 25 patients had a painful native knee with primary osteoarthritis (OA). Synovial fluid was obtained from each patient's affected knee. Appropriate lab and culture data was also obtained from...

Beyond the Implant: Retrieval Analysis Methods for Implant Surveillance, 2018

Journal of Bone and Joint Surgery-british Volume, 2017

INTRODUCTION Since the recall of some metal on metal (MoM) THR bearings, surgeons have seen patie... more INTRODUCTION Since the recall of some metal on metal (MoM) THR bearings, surgeons have seen patients with pain, elevated Co and Cr levels and adverse local tissue reactions (ALTR). While many variables may contribute to THR MoM failures, many times these variables are not present in patients who present with symptoms. We investigate the possible genetic predilection of a group of patients who were revised after MoM THR surgery for pain, high Co/Cr levels and ALTR. METHODS IRB approval was obtained prior to our study. We have analyzed 19 control (asymptomatic MoM THR patients > 6 years after surgery) and 19 disease (revised MoM THR for high metal ions and ALTR). The 38 sample intensity files were subject to sample Quality Control (QC) using Contrast QC (< 0.4) with an Affymetrix Genotyping Console. The resulting 38 sample files with genotype calls were loaded and further analyzed using the Association Workflow in Partek Genomics Suite 6.6 (Partek, Missouri). Hardy-Weinberg equi...

Journal of the American Academy of Orthopaedic Surgeons, 2021

Introduction:The term “outpatient” has a variety of meanings regarding the location of arthroplas... more Introduction:The term “outpatient” has a variety of meanings regarding the location of arthroplasty and the duration of stay postoperatively. The purpose of this systematic review was to evaluate the literature and more accurately define the term “outpatient.”Methods:A PubMed search (2014 to 2019) using the terms “outpatient AND arthroplasty” identified 76 studies; 35 studies that met the inclusion criteria were assessed to determine the definition of “outpatient.” The level of evidence, type of arthroplasty, location of surgery (hospital or ambulatory surgery center [ASC]), approach used for hip arthroplasty, number of patients, number of surgeons, and length of time the patients were kept at the location after surgery were evaluated.Results:Arthroplasties analyzed were total hip (11), total knee (seven), unicompartmental knee (five), and hip and knee (12). Only 16.8% of surgeries defined as outpatient hip or knee arthroplasty were done in a freestanding ASC, and 44.2% of patients ...

The Journal of Arthroplasty, 2020

Background: We hypothesized that preoperative cryoneurolysis of the superficial genicular nerves ... more Background: We hypothesized that preoperative cryoneurolysis of the superficial genicular nerves in patients with osteoarthritis would decrease postoperative opioid use relative to standard of care (SOC) treatment in patients undergoing total knee arthroplasty (TKA). Methods: Patients received either cryoneurolysis (intent-to-treat [ITT]: n ¼ 62) or SOC (ITT: n ¼ 62). The cryoneurolysis group received cryoneurolysis of the superficial genicular nerves 3e7 days before surgery plus a similar preoperative, intraoperative, and postoperative pain management protocol as the SOC group. The primary end point was cumulative opioid consumption in total daily morphine equivalents from discharge to the 6-week study follow-up assessment. Secondary end points included changes in pain and functional scores. Primary and secondary end points were assessed using ITT and per-protocol (PP) analyses. Results: The primary end point was not met in the ITT analysis (4.8 [cryoneurolysis] vs 6.1 [SOC] mg; P ¼ .0841) but was met in the PP analysis (4.2 vs 5.9 mg; P ¼ .0186) after excluding patients with medication deviations or missing follow-up data. Compared with the SOC group, the cryoneurolysis group had improved functional scores and numerical improvements in pain scores across all follow-up assessments, with significant improvements observed in current pain from baseline to the 72-hour and 2-week follow-up assessments and pain in the past week from baseline to the 12-week follow-up assessment. Conclusion: Findings from the PP analysis suggest that preoperative cryoneurolysis in patients with knee osteoarthritis can reduce opioid consumption and improve functional outcomes after TKA.

The Bone & Joint Journal, 2020

Aims This study aimed to determine if macrophages can attach and directly affect the oxide layers... more Aims This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. Methods Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment. Results On stainless steel, both nonactivated and activated cell groups were shown to have a significant increase in metal ion release for Cr, Fe, and Ni (p < 0.001, p = 0.002, and p = 0.020 respectively) compared with medium only and showed macrophage-sized corrosive pits on the stainless steel surface. On titanium alloy discs there was a significant in...

Orthopedic Clinics of North America, 2019

Previous studies have shown that topical tranexamic acid is effective in decreasing the need for ... more Previous studies have shown that topical tranexamic acid is effective in decreasing the need for blood transfusion and decreasing blood loss in patients with cemented total knee arthroplasty. Few studies have investigated topical tranexamic acid use with hybrid fixation techniques. Although there remains some controversy surrounding the use of intravenous or topical tranexamic acid, recent studies have shown that they have similar effectiveness and complication rates. This study found that topical tranexamic acid is as effective in decreasing the rate of blood transfusions for total knee arthroplasty with hybrid fixation as with cemented fixation. Topical tranexamic acid decreases blood loss and has a protective role, even in hybrid fixation total knee arthroplasty where there is no barrier to blood loss in the bone implant interface.

Orthopedics, 2016

Tibial anatomical landmarks for transverse plane rotation of the tibial tray have not been valida... more Tibial anatomical landmarks for transverse plane rotation of the tibial tray have not been validated. The current authors propose aligning the tibial tray with both the anterior tibial center point of rotation (ATCPR) and the femoral trochlear groove (FTG) to establish the ideal tibial tray rotation in total knee arthroplasty (TKA). When the tibial tray centerline was aligned with ATCPR and FTG lines, the mean range of motion (ROM) was 144.3° (preoperatively 145°) and tibial rotation range was 22.8 mm (preoperatively, 24.9 mm). When the tibial component was rotated 5 mm medially to the ATCPR, the knee ROM decreased in flexion with patellar subluxation, while it decreased in extension when rotated 5 mm laterally. This method identifies the ideal tibial tray rotation in TKA, at which maximal range of tibial rotation and knee ROM are achieved without obvious overriding of components. [ Orthopedics , 2016; 39(3):S67–S71.]

Orthopedics, 2016

With the large number of total knee arthroplasties being performed and expectations that these nu... more With the large number of total knee arthroplasties being performed and expectations that these numbers will be on the rise over the coming decades, efforts to provide cost-efficient care are of greater interest. The preferred design of knee arthroplasty implants has changed over time, with the original all-polyethylene tibial (APT) design being replaced by metal-backed tibial (MBT) components, as well as more recent considerations of newer APT designs. Modern APT components have been shown to have similar or superior outcomes than MBT components. Despite their limitations, APT components can be used to reduce the economic burden to the provider, medical institution, and health care system as a whole. There is a paucity of evidence-based literature directly comparing the cost associated with APT and MBT components. The purpose of this report is to review the literature to assess the available data regarding direct and indirect costs of both designs so that orthopedic surgeons can acc...

The Knee, 2016

This bilateral squat study tests whether people with anterior cruciate ligament (ACL) reconstruct... more This bilateral squat study tests whether people with anterior cruciate ligament (ACL) reconstruction have symmetric three-dimensional ground reaction forces (GRFs) and symmetric anterior-posterior (AP) translation rates of the femur with respect to the tibia when compared with healthy control subjects. We hypothesized that there would be no long-term asymmetry in knee kinematics and kinetics in ACL reconstructed subjects following surgery and rehabilitation. Position and GRF data were collected on eight ACL reconstructed and eight control subjects during bilateral squat. The rate of relative AP translation was determined for each subject. Principal component models were developed for each of the three GRF waveforms. Principal component scores were used to assess symmetry within the ACL reconstructed group and within the control group. ACL reconstructed knees analyzed in early flexion during squat descent displayed a four-fold greater rate of change in anterior translation in the rec...

Orthopedics, 2016

The objective of this study was to describe how tibiofemoral internal/external rotation varies in... more The objective of this study was to describe how tibiofemoral internal/external rotation varies in patients after total knee arthroplasty (TKA) when compared with control participants during a sit-to-stand (STS) maneuver. Motion analysis was used to measure internal/external knee rotation during STS in the control and TKA groups. Fourteen participants were included in the study. Six patients with 7 TKA knees (6 posterior stabilized and 1 cruciate-retaining TKA) were compared with 8 control participants with 8 knees from the current authors' laboratory database. Participants performed 3 STS maneuvers, and the average internal/external rotation of the femur with respect to the tibia was compared. All control participants and 2 TKA participants had internal rotation of the femur with respect to the tibia, whereas 4 TKA participants had external rotation, and 1 had no rotation during STS. Further investigation into the surgical and patient- and implant-related factors that affect thi...

Orthopedics, 2016

Post-cam designs for posterior-stabilized total knee arthroplasy (TKA) implants have evolved over... more Post-cam designs for posterior-stabilized total knee arthroplasy (TKA) implants have evolved over the last 2 decades. These designs have evolved from symmetric post and cam to asymmetric designs that include anterior post interactions to affect a kinematic change in full extension. All design changes have consequences on the resulting femorotibial contact kinematics and, depending on the amount of constraint built into the design, these changes may have significant consequences on the wear patterns on the tibial polyethylene insert. The current authors review the kinematic effects of symmetric and asymmetric cam designs and use a retrieval database of TKA implants obtained at the time of necropsy to show how different design variables may affect polyethylene wear patterns after 10 or more years of implantation or from modeled wear in simulators. More modern designs seem to have moved the post posteriorly and sloped the anterior aspect to avoid impingement of the anterior post in ter...

The Journal of Arthroplasty, 2016

Obesity is a problem that is increasing in prevalence in the United States and in other countries... more Obesity is a problem that is increasing in prevalence in the United States and in other countries, and it is a common comorbidity in patients seeking total joint arthroplasty for degenerative musculoskeletal diseases. Obesity, as well as commonly associated comorbidities such as diabetes mellitus, cardiovascular disease, and those contributing to the diagnosis of metabolic syndrome, have been shown to have detrimental effects on total joint arthroplasty outcomes. Although there are effective surgical and nonsurgical interventions which can result in weight loss in these patients, concomitant benefit on arthroplasty outcomes is not clear. Preoperative optimization of surgical risk in obese total joint arthroplasty patients is an important point of intervention to improve arthroplasty outcomes.

Orthopedic Clinics of North America, 2019

There has been an increased interest in the role of corrosion in total hip arthroplasty. This is ... more There has been an increased interest in the role of corrosion in total hip arthroplasty. This is based on reports of early implant failures and adverse local tissue reaction resulting from excessive corrosion at the modular interfaces of some implant designs. Orthopedic alloys are not selected based solely on their mechanical properties of strength, but rather because they possess the best balance between material properties of corrosion resistance and mechanical properties of strength. The passive layer of a metal oxide that develops on a surface of a metal serves a critical role in preventing corrosion. However, this protective layer is a dynamic structure. Aggressive corrosion occurs on implants when the kinetics of this oxide layer's destruction dominates over its generation. There is a spectrum of different types of corrosion defined by the environment and stability of the passive layer. Pitting is the localized dissolution of this protective metal oxide film. Crevice corrosion occurs with a similar mechanism but in an isolated environment that promotes corrosion. Fretting corrosion or mechanically assisted crevice corrosion (MACC) occurs with the addition of mechanical oscillating loads at the modular junction that disrupts this protective layer. Understanding this process is important to improve implant designs, surgical technique, and assessment of patients.

Handbook of Spine Technology, 2020

Materials, 2021

A correlation between patellar kinematics and anterior knee pain is widely accepted. However, the... more A correlation between patellar kinematics and anterior knee pain is widely accepted. However, there is no consensus on how they are connected or what profile of patellar kinematics would minimize anterior knee pain. Nevertheless, answering this question by merging existing studies is further complicated by the variety of ways to describe patellar kinematics. Therefore, this study describes the most frequently used conventions for defining patellar kinematics, focusing on the rotations. The similarities and differences between the Cardan sequences and angles calculated by projecting axes are analyzed. Additionally, a tool is provided to enable the conversion of kinematic data between definitions in different studies. The choice of convention has a considerable impact on the absolute values and the clinical characteristics of the patello-femoral angles. In fact, the angles that result from using different mathematical conventions to describe a given patello-femoral rotation from our a...

Orthopedic Clinics of North America

Journal of the American Academy of Orthopaedic Surgeons

Introduction: This study evaluated the effect of bupivacaine versus mepivacaine spinal anesthesia... more Introduction: This study evaluated the effect of bupivacaine versus mepivacaine spinal anesthesia and preoperative adductor canal block (ACB) on recovery, length of stay, pain, and complications of same-day discharge total knee arthroplasty (TKA) at a free-standing ambulatory surgery center. Methods: We performed a retrospective review of patients who underwent TKA between March 2018 and September 2019. The patients were grouped based on the neuraxial anesthetic regimen: bupivacaine with ACB, bupivacaine without ACB, and mepivacaine without ACB. Preoperative ACBs were discontinued in December 2018, and use of mepivacaine spinal anesthesia was initiated in March 2019. Length of stay in the postanesthesia care unit (PACU), time to controlled void and ambulation, postoperative pain, morphine milligram equivalents (MME), and transient neurologic symptoms were compared. Results: Ninety consecutive patients who underwent TKA were identified. Fifty patients received bupivacaine with ACB, 2...

Journal of Bone and Joint Surgery-british Volume, 2017

Introduction Total knee arthroplasty (TKA) is a successful procedure for end stage arthritis of t... more Introduction Total knee arthroplasty (TKA) is a successful procedure for end stage arthritis of the knee that is being performed on an exponential basis year after year. Most surgeons agree that soft tissue balancing of the TKA is a paramount to provide a successful TKA. We utilized a set of retrieved lower extremities with an existing TKA to measure the laxity of the knee in all three planes to see if wear scores of the implants correlated to the laxity measured. This data has never been reported in the literature. Methods IRB approval was obtained for the local retrieval program. Each specimen was retrieved after removing the skin, subcutaneous tissue and muscle from mid thigh to mid tibia. The femur, tibia and fibula were then transversely cut to remove the specimen for testing. Each specimen was then imaged using a flouroscopic imaging unit (OEC, Inc) in the AP, Lateral and sunrise views. These images were used to analyze whether there were any signs of osteolysis. Each specimen...

Journal of Bone and Joint Surgery-british Volume, 2017

Introduction Early hip OA may be attributed to smaller coverage of the femoral head leading to hi... more Introduction Early hip OA may be attributed to smaller coverage of the femoral head leading to higher loads per unit area. We hypothesize that tight hamstrings may contribute to increased loads per unit area on the femoral head during gait. When a patient has tight hamstrings they cannot flex their pelvis in a normal fashion which may result in smaller coverage of the femoral head (Figure 1). This study aimed to determine if subjects with tight hamstrings can improve femoral head coverage during gait after a stretching intervention. Methods Nine healthy subjects with tight hamstrings (popliteal angle>25°) were recruited and consented for this IRB approved study. Gait analysis with 58 reflective markers were placed by palpation on anatomical landmarks of the torso and lower extremities. Ten optoelectronic cameras (Qualisys, Gothenburg, Sweden) and three force plates (AMTI, Watertown, MA) were used to track marker position and measure foot strike forces. Subjects walked at a self-s...

Journal of Bone and Joint Surgery-british Volume, 2017

Introduction Gelsolin (GSN) is a protein whose function in the cytoplasm is to regulate intracell... more Introduction Gelsolin (GSN) is a protein whose function in the cytoplasm is to regulate intracellular actin assembly, while circulating plasma GSN has been implicated in the clearance of cellular byproducts via the body's scavenger system. In knee synovial fluid, GSN appears to be protective of inflammation as lower levels have been found in patients with rheumatoid arthritis while higher levels have been demonstrated in hypersensitivity reactions to metallic implants. The purpose of this study is to define the role of GSN in painful total knee arthroplasty (TKA) patients as a biomarker to distinguish septic from aseptic diagnoses. Methods After Institutional Review Board (IRB) approval, 50 patients were enrolled in the study into two cohorts. 25 patients presented with a painful TKA and 25 patients had a painful native knee with primary osteoarthritis (OA). Synovial fluid was obtained from each patient's affected knee. Appropriate lab and culture data was also obtained from...

Beyond the Implant: Retrieval Analysis Methods for Implant Surveillance, 2018

Journal of Bone and Joint Surgery-british Volume, 2017

INTRODUCTION Since the recall of some metal on metal (MoM) THR bearings, surgeons have seen patie... more INTRODUCTION Since the recall of some metal on metal (MoM) THR bearings, surgeons have seen patients with pain, elevated Co and Cr levels and adverse local tissue reactions (ALTR). While many variables may contribute to THR MoM failures, many times these variables are not present in patients who present with symptoms. We investigate the possible genetic predilection of a group of patients who were revised after MoM THR surgery for pain, high Co/Cr levels and ALTR. METHODS IRB approval was obtained prior to our study. We have analyzed 19 control (asymptomatic MoM THR patients > 6 years after surgery) and 19 disease (revised MoM THR for high metal ions and ALTR). The 38 sample intensity files were subject to sample Quality Control (QC) using Contrast QC (< 0.4) with an Affymetrix Genotyping Console. The resulting 38 sample files with genotype calls were loaded and further analyzed using the Association Workflow in Partek Genomics Suite 6.6 (Partek, Missouri). Hardy-Weinberg equi...

Journal of the American Academy of Orthopaedic Surgeons, 2021

Introduction:The term “outpatient” has a variety of meanings regarding the location of arthroplas... more Introduction:The term “outpatient” has a variety of meanings regarding the location of arthroplasty and the duration of stay postoperatively. The purpose of this systematic review was to evaluate the literature and more accurately define the term “outpatient.”Methods:A PubMed search (2014 to 2019) using the terms “outpatient AND arthroplasty” identified 76 studies; 35 studies that met the inclusion criteria were assessed to determine the definition of “outpatient.” The level of evidence, type of arthroplasty, location of surgery (hospital or ambulatory surgery center [ASC]), approach used for hip arthroplasty, number of patients, number of surgeons, and length of time the patients were kept at the location after surgery were evaluated.Results:Arthroplasties analyzed were total hip (11), total knee (seven), unicompartmental knee (five), and hip and knee (12). Only 16.8% of surgeries defined as outpatient hip or knee arthroplasty were done in a freestanding ASC, and 44.2% of patients ...

The Journal of Arthroplasty, 2020

Background: We hypothesized that preoperative cryoneurolysis of the superficial genicular nerves ... more Background: We hypothesized that preoperative cryoneurolysis of the superficial genicular nerves in patients with osteoarthritis would decrease postoperative opioid use relative to standard of care (SOC) treatment in patients undergoing total knee arthroplasty (TKA). Methods: Patients received either cryoneurolysis (intent-to-treat [ITT]: n ¼ 62) or SOC (ITT: n ¼ 62). The cryoneurolysis group received cryoneurolysis of the superficial genicular nerves 3e7 days before surgery plus a similar preoperative, intraoperative, and postoperative pain management protocol as the SOC group. The primary end point was cumulative opioid consumption in total daily morphine equivalents from discharge to the 6-week study follow-up assessment. Secondary end points included changes in pain and functional scores. Primary and secondary end points were assessed using ITT and per-protocol (PP) analyses. Results: The primary end point was not met in the ITT analysis (4.8 [cryoneurolysis] vs 6.1 [SOC] mg; P ¼ .0841) but was met in the PP analysis (4.2 vs 5.9 mg; P ¼ .0186) after excluding patients with medication deviations or missing follow-up data. Compared with the SOC group, the cryoneurolysis group had improved functional scores and numerical improvements in pain scores across all follow-up assessments, with significant improvements observed in current pain from baseline to the 72-hour and 2-week follow-up assessments and pain in the past week from baseline to the 12-week follow-up assessment. Conclusion: Findings from the PP analysis suggest that preoperative cryoneurolysis in patients with knee osteoarthritis can reduce opioid consumption and improve functional outcomes after TKA.

The Bone & Joint Journal, 2020

Aims This study aimed to determine if macrophages can attach and directly affect the oxide layers... more Aims This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. Methods Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment. Results On stainless steel, both nonactivated and activated cell groups were shown to have a significant increase in metal ion release for Cr, Fe, and Ni (p < 0.001, p = 0.002, and p = 0.020 respectively) compared with medium only and showed macrophage-sized corrosive pits on the stainless steel surface. On titanium alloy discs there was a significant in...

Orthopedic Clinics of North America, 2019

Previous studies have shown that topical tranexamic acid is effective in decreasing the need for ... more Previous studies have shown that topical tranexamic acid is effective in decreasing the need for blood transfusion and decreasing blood loss in patients with cemented total knee arthroplasty. Few studies have investigated topical tranexamic acid use with hybrid fixation techniques. Although there remains some controversy surrounding the use of intravenous or topical tranexamic acid, recent studies have shown that they have similar effectiveness and complication rates. This study found that topical tranexamic acid is as effective in decreasing the rate of blood transfusions for total knee arthroplasty with hybrid fixation as with cemented fixation. Topical tranexamic acid decreases blood loss and has a protective role, even in hybrid fixation total knee arthroplasty where there is no barrier to blood loss in the bone implant interface.

Orthopedics, 2016

Tibial anatomical landmarks for transverse plane rotation of the tibial tray have not been valida... more Tibial anatomical landmarks for transverse plane rotation of the tibial tray have not been validated. The current authors propose aligning the tibial tray with both the anterior tibial center point of rotation (ATCPR) and the femoral trochlear groove (FTG) to establish the ideal tibial tray rotation in total knee arthroplasty (TKA). When the tibial tray centerline was aligned with ATCPR and FTG lines, the mean range of motion (ROM) was 144.3° (preoperatively 145°) and tibial rotation range was 22.8 mm (preoperatively, 24.9 mm). When the tibial component was rotated 5 mm medially to the ATCPR, the knee ROM decreased in flexion with patellar subluxation, while it decreased in extension when rotated 5 mm laterally. This method identifies the ideal tibial tray rotation in TKA, at which maximal range of tibial rotation and knee ROM are achieved without obvious overriding of components. [ Orthopedics , 2016; 39(3):S67–S71.]

Orthopedics, 2016

With the large number of total knee arthroplasties being performed and expectations that these nu... more With the large number of total knee arthroplasties being performed and expectations that these numbers will be on the rise over the coming decades, efforts to provide cost-efficient care are of greater interest. The preferred design of knee arthroplasty implants has changed over time, with the original all-polyethylene tibial (APT) design being replaced by metal-backed tibial (MBT) components, as well as more recent considerations of newer APT designs. Modern APT components have been shown to have similar or superior outcomes than MBT components. Despite their limitations, APT components can be used to reduce the economic burden to the provider, medical institution, and health care system as a whole. There is a paucity of evidence-based literature directly comparing the cost associated with APT and MBT components. The purpose of this report is to review the literature to assess the available data regarding direct and indirect costs of both designs so that orthopedic surgeons can acc...

The Knee, 2016

This bilateral squat study tests whether people with anterior cruciate ligament (ACL) reconstruct... more This bilateral squat study tests whether people with anterior cruciate ligament (ACL) reconstruction have symmetric three-dimensional ground reaction forces (GRFs) and symmetric anterior-posterior (AP) translation rates of the femur with respect to the tibia when compared with healthy control subjects. We hypothesized that there would be no long-term asymmetry in knee kinematics and kinetics in ACL reconstructed subjects following surgery and rehabilitation. Position and GRF data were collected on eight ACL reconstructed and eight control subjects during bilateral squat. The rate of relative AP translation was determined for each subject. Principal component models were developed for each of the three GRF waveforms. Principal component scores were used to assess symmetry within the ACL reconstructed group and within the control group. ACL reconstructed knees analyzed in early flexion during squat descent displayed a four-fold greater rate of change in anterior translation in the rec...

Orthopedics, 2016

The objective of this study was to describe how tibiofemoral internal/external rotation varies in... more The objective of this study was to describe how tibiofemoral internal/external rotation varies in patients after total knee arthroplasty (TKA) when compared with control participants during a sit-to-stand (STS) maneuver. Motion analysis was used to measure internal/external knee rotation during STS in the control and TKA groups. Fourteen participants were included in the study. Six patients with 7 TKA knees (6 posterior stabilized and 1 cruciate-retaining TKA) were compared with 8 control participants with 8 knees from the current authors' laboratory database. Participants performed 3 STS maneuvers, and the average internal/external rotation of the femur with respect to the tibia was compared. All control participants and 2 TKA participants had internal rotation of the femur with respect to the tibia, whereas 4 TKA participants had external rotation, and 1 had no rotation during STS. Further investigation into the surgical and patient- and implant-related factors that affect thi...

Orthopedics, 2016

Post-cam designs for posterior-stabilized total knee arthroplasy (TKA) implants have evolved over... more Post-cam designs for posterior-stabilized total knee arthroplasy (TKA) implants have evolved over the last 2 decades. These designs have evolved from symmetric post and cam to asymmetric designs that include anterior post interactions to affect a kinematic change in full extension. All design changes have consequences on the resulting femorotibial contact kinematics and, depending on the amount of constraint built into the design, these changes may have significant consequences on the wear patterns on the tibial polyethylene insert. The current authors review the kinematic effects of symmetric and asymmetric cam designs and use a retrieval database of TKA implants obtained at the time of necropsy to show how different design variables may affect polyethylene wear patterns after 10 or more years of implantation or from modeled wear in simulators. More modern designs seem to have moved the post posteriorly and sloped the anterior aspect to avoid impingement of the anterior post in ter...

The Journal of Arthroplasty, 2016

Obesity is a problem that is increasing in prevalence in the United States and in other countries... more Obesity is a problem that is increasing in prevalence in the United States and in other countries, and it is a common comorbidity in patients seeking total joint arthroplasty for degenerative musculoskeletal diseases. Obesity, as well as commonly associated comorbidities such as diabetes mellitus, cardiovascular disease, and those contributing to the diagnosis of metabolic syndrome, have been shown to have detrimental effects on total joint arthroplasty outcomes. Although there are effective surgical and nonsurgical interventions which can result in weight loss in these patients, concomitant benefit on arthroplasty outcomes is not clear. Preoperative optimization of surgical risk in obese total joint arthroplasty patients is an important point of intervention to improve arthroplasty outcomes.

Orthopedic Clinics of North America, 2019

There has been an increased interest in the role of corrosion in total hip arthroplasty. This is ... more There has been an increased interest in the role of corrosion in total hip arthroplasty. This is based on reports of early implant failures and adverse local tissue reaction resulting from excessive corrosion at the modular interfaces of some implant designs. Orthopedic alloys are not selected based solely on their mechanical properties of strength, but rather because they possess the best balance between material properties of corrosion resistance and mechanical properties of strength. The passive layer of a metal oxide that develops on a surface of a metal serves a critical role in preventing corrosion. However, this protective layer is a dynamic structure. Aggressive corrosion occurs on implants when the kinetics of this oxide layer's destruction dominates over its generation. There is a spectrum of different types of corrosion defined by the environment and stability of the passive layer. Pitting is the localized dissolution of this protective metal oxide film. Crevice corrosion occurs with a similar mechanism but in an isolated environment that promotes corrosion. Fretting corrosion or mechanically assisted crevice corrosion (MACC) occurs with the addition of mechanical oscillating loads at the modular junction that disrupts this protective layer. Understanding this process is important to improve implant designs, surgical technique, and assessment of patients.

Handbook of Spine Technology, 2020

Materials, 2021

A correlation between patellar kinematics and anterior knee pain is widely accepted. However, the... more A correlation between patellar kinematics and anterior knee pain is widely accepted. However, there is no consensus on how they are connected or what profile of patellar kinematics would minimize anterior knee pain. Nevertheless, answering this question by merging existing studies is further complicated by the variety of ways to describe patellar kinematics. Therefore, this study describes the most frequently used conventions for defining patellar kinematics, focusing on the rotations. The similarities and differences between the Cardan sequences and angles calculated by projecting axes are analyzed. Additionally, a tool is provided to enable the conversion of kinematic data between definitions in different studies. The choice of convention has a considerable impact on the absolute values and the clinical characteristics of the patello-femoral angles. In fact, the angles that result from using different mathematical conventions to describe a given patello-femoral rotation from our a...