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Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_11 | Pages 3 - 3
1 Dec 2020
Grupp TM Schilling C Fritz B Reyna ALP Pfaff A Taunt C Mihalko WM
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Introduction

Beneath infection, instability and malalignment, aseptic tibial component loosening remains a major cause of failure in total knee arthroplasty (TKA) [1]. This emphasizes the need for stable primary and long-term secondary fixation of tibial baseplates. To evaluate the primary stability of cemented tibial baseplates, different pre-clinical test methods have been undergone: finite element analysis [2], static push-out [3,4] or dynamic compression-shear loading [5] until interface failure. However, these test conditions do not reflect the long-term endurance under in vivo loading modes, where the tibial baseplate is predominantly subjected to compression and shear forces in a cyclic profile [5,6].

To distinguish between design parameters the aim of our study was to develop suitable pre-clinical test methods to evaluate the endurance of the implant-cement-bone interface fixation for tibial baseplates under severe anterior (method I) and internal-external torsional (method II) shear test conditions.

Materials & Methods

To create a clinically relevant cement penetration pattern a 4th generation composite bone model was customised with a cancellous core (12.5 PCF cellular rigid PU foam) to enable for high cycle endurance testing. VEGA System® PS & Columbus® CRA/PSA ZrN-multilayer coated tibial baseplates (2×12) were implanted in the customised bone model using Palacos® R HV bone cement (Figure 1).

An anterior compression-shear test (method II) was conducted at 2500 N for 10 million cycles and continued at 3000 N & 3500 N for each 1 million cycles (total: 12 million cycles) simulating post-cam engagement at 45° flexion. An internal-external torsional shear test (method II) was executed in an exaggeration of clinically relevant rotations [7,8] with ±17.2° for 1 million cycles at 3000 N tibio-femoral load in extension. After endurance testing either under anterior shear or internal-external torsion each tibial baseplate was mounted into a testing frame and maximum push-out strength was determined [3].


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_10 | Pages 49 - 49
1 Oct 2020
Mihalko WM Gehlert R Jove M
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Introduction

In Europe a femoral neck retaining stem (Metha, Aesculap Inc, Tuttlingen, Germany) has been reported with excellent midterm survivorship. We report on a US series and compare it to a review of reports in Europe over the past decade to determine if US experience matches that in Europe.

Methods

A review of published studies was performed on PubMed with search terms: Hip, replacement, arthroplasty, and Metha. We found four publications that met the criteria of reporting survivorship and reasons for revision surgery. The results from these four articles combined had 4179 THA with the Metha stem. After IRB approval three orthopaedic groups in the US were used to combine their experience over the last 11 years. These US sources had 824 surgeries performed between 2008–2019. We then reported on all revisions for comparison of survivorship.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_9 | Pages 58 - 58
1 Oct 2020
Mihalko WM Heise G Morrow B Arnholt C Kurtz S
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Introduction

Pitting damage on implants has been reported and attributed to use of electrocautery. This study aimed to distinguish how different TKA bearing surfaces are susceptible to this type of damage and whether surgeons were aware that this damage can occur.

Methods

A survey was sent to Hip and Knee Society members to determine what percentage of adult reconstructive surgeons use electrocautery after implantation of components. Three bearing surfaces for primary TKA were selected: CoCr, Oxinium, and zirconium nitride (ZrN) to be damaged by electrocautery with a monopolar (MP, Bovie) and bipolar (BP, Aquamantys) electrocautery with three different energy settings. A comparison of surface damage and backscatter elemental analysis using SEM was performed. Average roughness (Ra), maximal peak-to-valley height (Rz,), kurtosis (Rk), and skewness (Rsk) measurements were collected using a profilometer (DektakXT, Bruker, Tucson, AZ) with a 2.5µm radius stylus to assess an area of 3.8mm by 3.2mm in the central portion of the area for each MP and BP energy setting used to impart damage to the bearing surfaces. A similar undamaged area for each bearing surface was also measured for roughness parameter comparison.


The Bone & Joint Journal
Vol. 102-B, Issue 7 Supple B | Pages 116 - 121
1 Jul 2020
Heise G Black CM Smith R Morrow BR Mihalko WM

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.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_12 | Pages 12 - 12
1 Oct 2019
Heise GM Black CM Morrow BR Smith RA Mihalko WM
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Introduction

Metal alloys have been commonly used for surgical applications due to their suitable mechanical characteristics and relatively good biocompatibility. However, direct cellular corrosion of orthopaedic implants remains a controversial topic and is still not fully understood. This study aims to examine a possible aspect of this corrosion mechanism by determining if macrophages can attach and directly affect the surfaces of 316L stainless steel, Ti6Al4V, and CoCrMo by releasing components of the alloy oxide layer.

Methods

IC-21 ATCC peritoneal macrophages were cultured with growth medium of RPMI 1640 with 10%FBS, L-glutamine, and gentamicin. Interferon Gamma (IFNy) and Lipopolysaccharide (LPS) were used to induce activation of macrophages. Stainless Steel, CoCr, and Titanium disks cut, polished, and placed into a 96 well plate. Stainless steel testing included 6 groups: standard medium, 20,000 cells, 40,000 cells, 20,000 activated cells, 40,000 activated cells. CoCr and Ti testing included the following: medium, 40,000 cells, 20,000 activated cells, cells, no disk + 20,000 cells, no disk + 40,000 cells. After cells were attached to the surface, culture media was replaced and collected every 24 hours for stainless steel and every 12 hours for Ti and CoCr. ICP-MS, conducted at Brooks Applied Labs (Bothell, WA), was used to determine metal concentrations found in the supernatant.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_11 | Pages 69 - 69
1 Oct 2019
Mihalko WM Kerkhof A Guyton JL Crockarell JR Harkess JW Ford MC
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Introduction

Even as the outcomes of primary total knee arthroplasty (TKA) continue to improve, there remain increasing concerns about pain control after surgery and prolonged narcotic use. Cryoneurolysis has been demonstrated to reduce osteoarthritis knee pain for up to 90 days. We hypothesized that postoperative narcotic use could be reduced following preoperative cryoneurolysis of the superficial genicular nerves.

Methods

Primary TKA patients were randomized into either a control or cryoneurolysis treatment group. Both followed the same preoperative, intraoperative, and postoperative pain management protocol, except the treatment group had cryoneurolysis of their superficial genicular nerves 3–7 days prior to surgery. All patients were prescribed 40 narcotic pills at discharge and pills were counted at 72 hours and at 2,6, and 12 weeks postoperatively. The primary endpoint was daily morphine equivalent (DME) based on pill count and secondary endpoints were changes in pain and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, Jr.) scores.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_12 | Pages 45 - 45
1 Oct 2018
Mihalko WM Richey PA Johnson KC Singhal K Neiberg RH Bahnson JL
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Introduction

Overwhelming evidence has established obesity as a risk factor for osteoarthritis (OA) of the knee. Randomized clinical trials such as the Look AHEAD study have shown long term successful intentional weight loss with an intensive lifestyle intervention (ILI) in overweight and obese type 2 diabetics. Weight loss can also decrease knee pain in persons who have OA, but it is unknown if intentional weight loss can reduce the risk of TKR. To answer this question, data from the Look AHEAD study were examined to determine if intentional weight loss could reduce the risk of TKR.

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.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 587 - 588
1 Nov 2011
Froelich JM Novicoff WM Mihalko WM Saleh KJ
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Purpose: The purpose of this study was to examine the effects of baseline mental health on functional outcomes after primary knee arthroplasty by reviewing the data collected in a multi-center prospective observational cohort study. We hypothesized that those patients with lower baseline mental health status would demonstrate significantly worse outcomes vs. their counterparts with higher mental status following primary total knee arthroplasty.

Method: Data from a multi-center prospective cohort study of PS (posterior stabilizing implant) and CR (cruciate retaining implant) primary knee arthroplasty were compared to determine the relationship between baseline mental health status and functional outcomes post-surgery. Subjects were followed from the time of the index surgery to monitor outcomes and complications. Validated quality of life instruments, including SF-36, WOMAC, Knee Society Score, and an activity scale were used. The rates of improvement from 0 to 12 months were analyzed for this study.

Results: Baseline data was available for 436 subjects in the primary PS study and 493 subjects in the primary CR study. Patients improved significantly on all SF-36 and WOMAC components between baseline and 12 months post-surgery. Correlation and regression analysis between WOMAC and SF-36 showed that Global Health (GH), Mental Health (MH), and Mental Component Score (MCS) subscales on the SF-36 were significantly associated with positive post-operative changes in WOMAC scores.

Conclusion: This study examined the effects of baseline mental health on functional outcomes after primary knee arthroplasty and found that baseline mental health was a significant predictor of functional outcomes twelve months after surgery. This relationship between mental health and outcomes needs to be examined carefully to help surgeons better prepare their patients for surgery.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 24 - 24
1 Mar 2010
Saleh KJ Mihalko WM Brown TE Cui Q Novicoff W
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Purpose: Comorbidities in patients undergoing total joint arthroplasty continue to be a challenging problem. Retrospective studies have demonstrated that co-morbidities affect outcomes of revision total knee arthroplasty (RTKA). However, the relationship between the outcomes of RTKA and co-morbidities has not been well established. This prospective randomized study was undertaken to investigate these relationships.

Method: A prospective cohort study (the North America Knee Arthroplasty Revision Study) was conducted to examine factors that predict outcomes after RTKA. 308 subjects met inclusion/exclusion criteria. Subjects were followed from the time of the index surgery for a minimum of two years to monitor outcomes and complications. Validated quality of life instruments, including SF-36, WOMAC, Knee Society Score, and an activity scale were used. The rates of improvement from 0 to 12 and 12 to 24 months were analyzed.

Results: There were 145 males and 163 females. The mean age was 68.7 years. Mean time from primary procedure to RTKA was 7.9 years. Arthroplasty failure was classified as aseptic in 82% and septic in 18% of the cases. Hypertension was seen in 62.4%, back pain in 50%, heart disease in 25.9%, diabetes mellitus in 23.9%, gastric ulcers in 17.9%, and rheumatoid arthritis in 16.6%. Less frequent co-morbidities included anemia, cancer, kidney disease, lung disease and liver disease.

Conclusion: Analyses showed that the number of reported co-morbidities was the most significant predictor of outcomes, consistently forecasting poorer functional improvement on all measures. The results indicated that ultimate treatment of co-morbidities before and after surgery may improve outcomes of RTKA. Comorbidities in patients undergoing revision TKA can be a challenging problem. This study showed that the number of reported co-morbidities was the most significant predictor of poorer outcomes.