Monday, December 31, 2012

New DePuy Hip Replacement Side Effect Reported

. By
Montreal, Canada: Patients who have filed a DePuy lawsuit following revision surgery to remove a metal-on-metal DePuy hip replacement are already aware of the pain caused by metallosis. But researchers in Canada may have found another side effect that could be attributed to metal-on-metal hip devices such as the DePuy ASR, at least according to a recently published study.

The study was published in December in the journal Orthopedics, and details the condition of a 54-year-old female patient who received a metal-on-metal hip replacement. According to researchers, the patient developed swelling in her leg five years after hip replacement surgery and this swelling grew worse when the patient walked. The leg swelling was "secondary to venous obstruction by a metallosis-induced iliopsoas bursal cyst associated with markedly elevataed intralesional cobalt and chromium levels."

In other words, after having a metal-on-metal hip replacement, the patient experienced metallic debris coming loose from the device and being absorbed by her bloodstream. This caused a bursal cyst on her iliopsoas, which compressed her femoral vein. The bursal cyst had increased levels of chromium and cobalt.

Researchers noted the patient underwent revision surgery to replace the metal-on-metal hip device with a ceramic-on-ceramic hip device and at one-year follow-up did not have any signs of recurrence of the cyst.

   "Metal-on-metal bearings of the hip are associated with elevated concentrations of metal ions in the hip joint and systemically," researchers noted. These elevated metal concentrations can cause adverse reactions, including build-up of fluids, and the development of lesions, cysts and pseudotumors

Saturday, December 29, 2012

Before Metal-on-Metal Hip Surgery, Consider Imaging, Symptoms

Healio

Researchers from the United Kingdom recommend patients who have received fatly metal-on-metal hip implants consider both MRI imaging and symptoms before undergoing revision surgeries.
“Although ultrasound and MRI are useful in the treating of metal-on-metal patients, there is a significant percentage of hips that have pain with negative radiology findings,” Naveed Ahmed, MBBS, MSc, of Prince Charles Hospital in Merthyr Tydfil, United Kingdom, stated in his presentation at the British Orthopaedic Association Congress, Healio.com said.

Ahmed and his team of researchers retrospectively studied imaging results from 25 hips between March 2011 and May 2012: 23 hips had ultrasound scans and 21 of these hips also had MRI scans preoperatively, Healio.com said. The patients’ average age range was 37 years to 69 years and ultrasound was conducted an average of 50 months after primary total hip replacement, Healio.com said.

Researchers examined fluid collected from patients during revision surgery in search of evidence of metallosis. MRIs were positive for fluid collection in 16 patients, and ultrasound was positive in 18 patients, Healio.com said. Four patients had both negative MRI and ultrasound results, but were still revised due to pain and were found to have histopathology positive metallosis. The histopathologist involved in the study defined metallosis as the presence of sheets of macrophages with dark brown pigmentation in the cytoplasm under polarized light, Healio.com said. The results also revealed that one patient had a positive ultrasound and negative MRI result. Likewise, one patient had a positive MRI with a normal ultrasound.

Serum cobalt and chromium levels elevated after metal disc arthroplasty

Healio

Gornet MF. Eur Spine J. 2012. doi:10.1007/s00586-012-2581-8.

Blood samples for 24 patients with a single-level all-metal total lumbar disc arthroplasty prosthesis collected through 36 months postoperatively showed higher serum cobalt and chromium levels of the same order of magnitude as those seen at similar time points in patients with well-functioning metal-on-metal hip implants.

"In general, these results indicated that serum Co [cobalt] and Cr [chromium] levels are elevated at all postoperative time points," Matthew F. Gornet, MD, and colleagues wrote in their study abstract.
The 13 men and 11 women included in the study had an average age of 41 years when they had a Maverick Lumbar Disc (Medtronic; Memphis, Tenn.) implanted at either L4/5 (eight patients) or L5/S1 (16 patients).

Investigators conducted this prospective longitudinal study using high-resolution inductively-coupled plasma-mass spectometry for the serum assay. They found median serum Co levels of 0.10 ng/mL and Cr levels of 0.06 ng/mL, preoperatively. However, median 36-month postoperative serum measurements reached 0.52 ng/mL for Co and 0.50 ng/mL for Cr, according to the abstract.
Gornet and colleagues noted in the discussion section of the study that the median Co and Cr serum levels they measured were one-third those in some total disc arthroplasty studies in the literature, and the median serum Cr levels they reported were the same as or lower than in studies of patients with stainless steel posterior spine instrumentation.

DePuy Settlement Approved in Australian Class Action

Australian plaintiff Pamela Casey filed a DePuy lawsuit in 2010, claiming problems with the LCS Duofix Femoral knee implant. Though the implant was withdrawn from the Australian market in 2009, thousands of patients were implanted with the device. According to the settlement agreement, those who had to go through revision surgery will receive about $31,000 each. Meanwhile, DePuy also faces thousands of plaintiffs who have filed a DePuy hip lawsuit in the U.S. because of DePuy hip complications with the ASR or the Pinnacle implants. The ASR was removed from the market in the 2010 DePuy hip recall.

According to the Therapeutic Goods Administration (TGA)—part of the Australian government that is responsible for regulating therapeutic goods—J&J recalled all batches of the LCS Duofix Knee Replacement Femoral Component and voluntarily ceased supply of the product in Australia in July 2009. The TGA became aware of issues with the component after hospitals and surgeons notified the Australian sponsor, J&J Medical Pty Ltd., of problems with the implant.

DePuy conducted an investigation and later stated, “microscopic particles of a substance used in the manufacturing process may sometimes enter the area surrounding the implant. While the particles do not react with the body, they may potentially cause increased wear of the implant and subsequent symptoms of pain and swelling.” The TGA received over 100 adverse event reports for the component.

Under the terms of the DePuy settlement, patients who received the LCS Duofix Femoral knee implant who had to undergo revision surgery will receive about $31,000 each. Those who required two or three additional surgical procedures will receive $65,000 each. More may be awarded in certain cases, determined on an individual basis.



Meanwhile, J&J and DePuy face thousands more plaintiffs who have filed complaints concerning the DePuy ASR metal-on-metal hip implant. The ASR was withdrawn from the market in the 2010 DePuy hip recall. Additional lawsuits have been filed concerning problems with the Pinnacle system, which is also a metal-on-metal device. Both have been linked with DePuy hip complications including pain, instability, metal contamination, swelling, premature loosening, and implant failure.
So far, J&J has agreed to settlements with plaintiffs in three DePuy hip lawsuits filed in Nevada, paying about $200,000 each.

Younger, Taller and Heavier Patients More Likely to Require Hip Revision Surgery

Drug Watch

People who are younger, taller and heavier are more likely to need revision surgery after a primary total hip replacement surgery, according to a new study. The study is the first of its kind in the United States.

The results of the study were published in the December issue of Arthritis Care & Research, a journal of the American College of Rheumatology. The study authors – Dr. Elizabeth Wright and colleagues – reviewed the Medicare claims of people from 29 states that had a primary total hip replacement between July 1995 and June 1996 and followed up with these patients through December 2008.

The results revealed that people who received a cemented femoral component and were age 75 or younger, taller and heavier had the greatest chance of needing a revision surgery. Other factors that increased the need for revision surgery were undergoing a prior contralateral primary total hip replacement or other prior orthopedic surgery and living with others.

According to the authors, “Effects of age and body size on revision risk should be addressed by clinicians with patients considering primary total hip replacement.”

High Rates of Revision Surgery in Recalled Implants

In 2010, there were almost 460,000 hip replacement surgeries performed in the United States – and 58,000 of those were revision surgeries. Normally, natural wear and tear is the primary reason why people need hip revision surgery, but a number of metal-on-metal implants like Johnson &Johnson’s DePuy ASR XL Acetabular System are implicated in premature revision surgery rates.

This device was used in almost 100,000 hip replacement procedures globally. Johnson & Johnson recalled the DePuy ASR in August 2010 after reports of premature device failure from loosening, metal poisoning called metallosis that caused tissue death around the joint and a host of other problems. In the United States, about 37,000 of the devices were recalled after being implanted.
Studies on the failure rate revealed an abnormally high 12 percent revision rate in the device, the highest in the industry.

First J&J Hip Lawsuits Settle

The first three of about 8,000 DePuy ASR lawsuits settled in August 2012. According to Bloomberg, the plaintiffs who alleged the implants were defective will get $200,000 each.

The plaintiffs claimed that the metal-on-metal design of the DePuy ASR caused harmful levels of metal debris to be released into the blood stream. They required revision surgery for pain and other harmful side effects. Tests showed bone damage and health problems resulting from the metal debris in all three plaintiffs.

The recall of the DePuy ASR reportedly cost Johnson & Johnson about $800 million. The company may spend as much as $2 billion to resolve thousands of pending faulty hip lawsuits, according to experts. Any cases not settled will go to trial.

Because of the high number of federal cases, the suits were consolidated into multidistrict litigation (MDL) in the U.S. District Court for the Northern District of Ohio (Toledo).

Wednesday, December 26, 2012

Oxidative Stress and Cancer: Representing that your medical condition is "stable" in order to collect pain and suffering claims from Depuy.

I hope everyone had a great holiday!

As a result of my reading the offer from Depuy to allow claims to be made in Australia for pain and suffering, I thought that it would interesting to remind patients of the  relationship between oxidative stress and Cancer.

How is this related to the litigation process in Australia?  In order to collect on this claim, you have to have a "stable condition."  Now, I have no idea what that means given the lack of "good data" on the systemic effects of the chromium and cobalt on your bodies.  In short, how does a patient claim they are stable?

We know from the medical journal article  "Evidence thus Far" that oxidative stress is generated from the chemical decomposition of the metals in the body.  I have published extensively on this.  See these URLs for more background on this/ especially those posts  starting with 7a:

Metal-on-metal bearings: THE EVIDENCE SO FAR

Does early intervention prevent bone/soft tissue loss: What is the outcome of revision surgery?

Do we know the threshold for revision surgery? (2of 7)

Is there an accepted cut-off level for blood metal ion levels? (3 of 7)

What is the significance of Gender with the Metal on Metal hips (4 of 7)

What is the frequency of adverse metal reactions with the MoM hips? (5 of 7)

What do plain radiographs, ultrasound, MRI and CT offer the Depuy hip patient (6 of 7)

Systemic effects of metal debris (7a of 7)

Systemic effects of metal debris (7b of 7)

Systemic effects of metal debris (7c of 7)

Systemic effects of metal debris (7d of 7)

Systemic effects of metal debris (7e of 7); excerpts from the committee on Mutagneicity

Systemic effects of metal debris (7f of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7g of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7g of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7h of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7i of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7j of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7k of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7L of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7M of 7); excerpts from the Committee on Mutagenicity

Systemic effects of metal debris (7N of 7); excerpts from the Committee on Mutagenicity
 
 
Now that we have established a  connection between the oxidative stress, chromium and cobalt and cancer, lets look at the general literature in Pub med.
 
Query one:  How many articles discuss the link between oxidative stress AND cancers:  11, 391 peer review journal articles.
 
Query two:  How many journal articles discuss : Oxidative stress CAUSES cancer:  5, 856 journal articles.
 
Query three: How many journal articles discuss oxidative stress and chromium and cobalt:  30
 
Query four: How many journal articles discuss oxidative stress and orthopaedic surgery:  141
 
 
With all of these publications discussing the relationship between  metal debris, cancer and mutagenicity, how is a patient supposed to claim they have a "stable medical condition?"
 
Here is a brief overview on the chemistry of this process in case you needed to be reminded :
 
Detailed studies in the past two decades have shown that redox active metals like iron (Fe), copper (Cu), chromium (Cr), cobalt (Co) and other metals undergo redox cycling reactions and possess the ability to produce reactive radicals such as superoxide anion radical and nitric oxide in biological systems. Disruption of metal ion homeostasis may lead to oxidative stress, a state where increased formation of reactive oxygen species (ROS) overwhelms body antioxidant protection and subsequently induces DNA damage, lipid peroxidation, protein modification and other effects, all symptomatic for numerous diseases, involving cancer, cardiovascular disease, diabetes, atherosclerosis, neurological disorders (Alzheimer's disease, Parkinson's disease), chronic inflammation and others. The underlying mechanism of action for all these metals involves formation of the superoxide radical, hydroxyl radical (mainly via Fenton reaction) and other ROS, finally producing mutagenic and carcinogenic malondialdehyde (MDA), 4-hydroxynonenal (HNE) and other exocyclic DNA adducts.
 
Here again is the diagram illustrating the process that occurs when Cr and Co are introduced into the body.

Zoll CEO Packer on device tax repeal efforts: No pessimists on the front lines

 

December 20, 2012 by Arezu Sarvestani

 
Zoll CEO Rick Packer says that tax repeal advocates on the front lines of the discussions with Washington are optimistic that the levy on device makers will be addressed before it hits in January.
Zoll CEO Richard Packer
As the medical device excise tax creeps closer to its planned launch date, all eyes are on Congress to see whether medtech lobbying efforts will yield a win for the industry.

While lawmakers weigh the tax and argue their way toward the so-called fiscal cliff, device industry stakeholders are placing their bets on whether or not the excise tax will survive until January.


Device makers need many months, millions of dollars to figure out medtech tax compliance

December 18, 2012 by MassDevice staff

The burden posed by the coming medical device tax is more than a 2.3% cut of revenues – it means millions in administrative costs and months of preparation to decipher new tax codes and develop systems for compliance.
accounting image
Medical device industry lobbying groups warned that the tax slated to take effect on January 1 will cost the industry more than the $30 billion it's slated to raise over 10 years - it could cost upwards of $660 million annually in implementation costs alone

Based on a small survey of 81 respondents representing a broad range of medtech companies, the sales tax will require months of preparation and millions in yearly administrative costs, adding to the 2.3% top-line cut the measure is designed to yield in support of healthcare reform.

Politics and pessimism aren't slowing medical device tax repeal efforts

December 14, 2012 by Arezu Sarvestani

Spirits remain high among medical device industry advocates pushing for repeal of the 2.3% medtech tax, despite political obstacles.
MassDevice.com coverage of the medical device tax
Political roadblocks aren't dampening the spirits of medtech industry advocates pushing for repeal of the looming medical device tax, despite the fact that the levy's slated to take effect in less than 3 weeks.

Even President Barack Obama's on-camera refusal to support a delay for the medical device tax last night hasn't curbed the enthusiasm.


Medical device tax: GOP group demands Dems sign petition for repeal

December 14, 2012 by MassDevice staff

The National Republican Congressional Committee launches a petition campaign, demanding that more Democratic senators sign on in support of repealing a 2.3% levy on medtech sales or else "pave the way for the job-killing medical device tax."
NRCC's medical device tax repeal petition
The National Republican Congressional Committee launched a petition campaign to rally support for repeal of the 2.3% medical device tax contained in President Barack Obama's Affordable Care Act.
The group sent the petition to a handful of Democratic senators, asking that they either sign their names in support of striking the levy or "pave the way for the job-killing medical device tax."


Words of caution for device tax repeal efforts | MassDevice.com On Call

December 14, 2012 by MassDevice staff

As more voices join the urgent call for repeal of the medical device tax, some caution against depriving the Affordable Care Act of the nearly $30 billion in funding the tax is expected to raise over 10 years.
MassDevice On Call
MASSDEVICE ON CALL — As more lawmakers join the medical device industry in calling for a repeal or delay of the medical device tax that's slated to hit January 1, some groups sought to temper the growing enthusiasm with words of warning

President Obama defends the medical device tax (video)

December 14, 2012 by MassDevice staff

President Barack Obama tells reporters that he's unwilling to consider delaying the medical device tax because healthcare reform is "going to be great for business."


http://www.youtube.com/watch?v=Ph7vtUITy8Y&feature=player_embedded


President Barack Obama took a hard stand against efforts to repeal or delay the 2.3% medical device tax taking effect in January.

The tax was created through the Affordable Care Act and is designed to raise around $30 billion over 10 years to help support various facets of healthcare reform.

Fiscal cliff debates bring more talk of medtech tax repeal | MassDevice.com On Call

December 11, 2012 by MassDevice staff

Advocates of repealing the medical device tax see opportunities during the discussions about the so-called "fiscal cliff" Congress faces at the start of next year.
MassDevice On Call
MASSDEVICE ON CALL — Opponents of the 2.3% medical device tax are looking for opportunities to address their concerns during the Congressional debates of the so-called "fiscal cliff."
The discussions may be gaining momentum as more voices in the House and Senate call for either repeal or delay in implementation for the tax, which takes effect January 1.

Medical device tax: Survey shows pessimism that repeal efforts will work

December 19, 2012 by MassDevice staff

A MassDevice.com survey of medical device industry stakeholders finds that a majority are pessimistic that the medical device tax will be repealed.
 
MassDevice.com coverage of the medical device tax

Sentiments within the medical device industry aren't as rosy as they appear from the perspective of the lobbying groups, according to the results of a snap survey conducted by MassDevice.com.

While a trio of industry lobbying groups has been campaigning for repeal of the 2.3% medical device tax that's slated to take effect at the start of the year, the view from within seems to be that the tax is here to stay- and not enough is being done to fight it.

Publicly traded medical device companies shed about 7,000 jobs in the 2012, representing 1.6% of the industry's U.S. jobs base.

Mass Devices 12 25 12

High-ranking medical device makers cut about 7,000 American jobs in 2012, representing about 1.6% of the industry's total U.S. workforce, according to a Reuters report.

Some of those cuts include layoffs at Boston Scientific (NYSE:BSX), St. Jude Medical (NYSE:STJ) and Stryker (NYSE:SYK), some of which were explicitly blamed on the impending medical device tax hitting the industry in just over a week.

Industry lobbying groups have warned that about 43,000 medtech jobs may be lost as a result of the 2.3% medical device excise tax taking effect at the start of 2013, but many of the layoff decisions made in 2013 were unrelated to the new fee.

Layoff measures in 2012, which included more than 2,000 cuts in a span of 2 months, were frequently the result of company overhauls and acquisitions, although the tax did play a feature role.

In recent months, Stryker has announced that it's on track for the 1,000 layoffs it planned to conduct before the end of this year in anticipation of a $150 million tab for compliance with the medical device tax.

Stryker initially announced the layoffs in November 2011, saying at the time that the reductions, which represent about 5% of its workforce, should free up capital for strategic investments and growth "despite the ongoing challenging economic environment and market slowdown in elective procedures."

Last month GE Healthcare (NYSE:GE) announced that it planned to lay of about 10% of its Vermont workforce, but declined to disclose how many jobs that would be.

In October healthcare giant Abbott (NYSE:ABT) cut 550 positions and said there would be more layoffs over the next year.

Although some medical device makers blamed the tax directly for their layoffs, including Stryker and Welch Allyn, which announced in September that it will shed about 10% of its global workforce, or 275 jobs, to compensate for the device tax, analysts suspect that industry layoffs are inevitable in the face of sinking sales, Reuters reported.

Medical device maker Covidien (NYSE:COV) explicitly stated in May that it's 200 layoffs and decision to shift some production overseas were entirely unrelated to the tax.

"While we believe the medical device tax may hurt investment in innovation and research & development, Covidien has never cited the device tax as a reason for laying off employees or transferring production to other locations," a company spokeswoman told MassDevice.com at the time.

"It's easy to blame the tax, but it's something that would have happened eventually at these companies," Frost & Sullivan analyst Venkat Rajan told the news wire.

"This [tax] is not what started the deterioration of the environment, but the tax is out of their control, so they can point to it as a catalyst and cry foul," Morningstar analyst Alex Morozov told Reuters. "They don't want the public to realize that what they should have done is cut infrastructure a long time ago."

Some medical device makers have similarly cried foul on the implication that the tax alone would drive cuts. In September Glottal Enterprises' CEO Martin Rothenberg told reporters that he had done the math and concluded that the device tax would result in marginal increases in product prices and "zero effect on sales" if the company could successfully market an effective product.

"It would surely not lead us to lay off employees or shift to overseas production," he wrote.
And Rothenberg certainly wasn't the 1st to cast a wary eye on industry warnings of tax-related layoffs. A report released by Bloomberg in June called out the medtech industry for its claims against the tax, saying that the alleged costs to jobs and innovation are "either untrue or exaggerated."
"Congress may well withdraw the medical-device tax," Bloomberg wrote. "If it does, it won't be because the industry mustered a strong economic case. It will be because it's too easy to pull the wool over lawmakers' eyes."

Device makers, on the other hand, have maintained that the tax will undeniably affect U.S. jobs and innovation and threaten the U.S.'s leadership in the global medtech market.

The industry is still actively lobbying to either delay the tax from its January 1 implementation date or repeal it altogether, hoping to wedge the tax into fiscal cliff negotiations in Congress.

"The tax is a very significant factor, but also should be placed in the context of the other challenges," AdvaMed president & CEO Stephen Ubl told the news wire.

Although analysts sought to temper arguments that the tax was the driving factor in a general financial down-shift in the medtech industry, they noted that the tax "will only exacerbate the problems the industry already faces," Reuters reported.

Monday, December 24, 2012

Revision Total Hip Arthroplasty Quiz

:  (Resident of Harvard orthopedics program)

Orthobullets

[ From connie :Nice summary of the indications and issues surrounding hip revisions.  I have read all of  my post op reports and have never seen a  bone loss classification scheme applied to my revision surgery.  I have to ask about this.  It would seem that if the surgeons used this scheme, it would provide some additional information on the actual bone loss that occurred to the different bones prior to revision?  I also notice that the ilium was not included.  In MoM revisions, you surely loose a good bit of bone in that region.  Not sure why it is not on this list?]

Introduction
  • Indications
    • osteolysis
    • loosening
    • instability
    • infection
    • mal-alignment
    • polyethylene wear
  • Options include
    • acetabular component revision
    • femoral head and polyethylene exchange
    • femoral component revisions
    • conversion from a hip arthrodesis
  • Complications
    • significantly higher than primary hip reconstruction
    • include
      • dislocation (even is simple procedures)
      • infection
      • nerve palsy
      • cortical perforation
      • fractures
      • DVT
      • limb length inequalities
Classification of Bone Loss
  • Acetabulum
AAOS Classification of Acetabular Bone Loss
Type I (segmental) Loss of part of the acetabular rim or medial wall
Type II (cavitary) Volumetric loss in the bony substance of the acetabular cavity
Type III (combined deficiency)Combination of segmental bone loss and cavitary deficiency
Type IV (pelvic discontinuity) Complete separation between the superior and inferior acetabulum
Type V (arthodesis)Arthrodesis
Proposky Classification of Acetabular Bone Loss
Type IMinimal deformity, intact rim
Type IIASuperior bone lysis with intact superior rim
Type IIBAbsent superior rim, superolateral migration
Type IICLocalized destruction of medial wall
Type IIIABone loss from 10am-2pm around rim, superolateral cup migration
Type IIIBBone loss from 9am-5pm around rim, superomedial cup migration
  • Femur
AAOS Classification of Femoral Bone Loss
Type I (segmental)Loss of bone of the supporting shell of femur
Type II (cavitary)Loss of endosteal bone with intact cortical shell
Type III (combined)Combination of segmental bone loss and cavitary deficiency
Type IV (malalignment)Loss of normal femoral geometry due to prior surgery, trauma, or disease
Type V (stenosis)Obliteration of the canal due to trauma, fixation devices, or bony hypertrophy
Type VI (femoral discontinuity)Loss of femoral integrity from fracture or nonunion
Proposky Classification of Femoral Bone Loss
Type IMinimal metaphyseal bone loss
Type IIExtensive metaphyseal bone loss with intact diaphysis
Type IIIaExtensive metadiaphyseal bone loss, minimum of 4 cm of intact cortical bone in the diaphysis
Type IIIbExtensive metadiaphyseal bone loss, less than 4 cm of intact cortical bone in the diaphysis
Type IVExtensive metadiaphyseal bone loss and a nonsupportive diaphysis
Presentation
  • Symptoms
    • groin pain --> acetabulum
    • thigh pain --> femoral stem
    • start-up pain --> component loosening
    • night pain --> infection
Imaging
  • Radiographs
    • required views
      • AP pelvis
      • orthogonal views of involved hip
      • full-length femur radiographs
    • additional views
      • pre-operative radiographs
      • immediate post-operative radiographs
      • judet views
        • useful for assessment of columns
  • CT scan
    • useful for determining extent of osteolysis
      • radiographs frequently underestimate extent of osteolysis
    • assessment of component position
Evaluation
  • Laboratory analysis
    • infectious laboratories
      • ESR
      • CRP
      • CBC
  • Aspiration
    • recommended if infectious laboratories are suggestive of infection
Treatment
  • Femoral revision
    • primary total hip arthroplasty components
      • indications
        • minimal methaphyseal bone loss
    • uncemented extensively porous-coated long stem prosthesis (or porous-coated/grit blasted combination)
      • indications
        • most Paprosky II and III defects
      • outcomes
        • 95% survival rate at 10-years
    • impaction bone grafting (Ling's technique)
      • indications
        • large ectactic canal and thin cortices
      • outcomes
        • most common complication is stem subsidence
    • modular oncology components
      • indications
        • massive bone loss with a non-supportive diaphysis
    • cemented stems
      • indications
        • irradiated bone
        • elderly
        • low-demand patients
      • outcomes
        • high failure rate
  • Acetabular revision
    • porous-coated hemisphere cup secured with screws
      • indications
        • rim is competent (> 2/3 of rim remaining)
    • reconstruction cage with structural bone allograft
      • indications
        • rim is incompetent (<2/3 of rim remaining)
      • outcomes
        • allograft failure is the most common complication
        • high failure rate (40-60%) without reconstruction cage due to component migration after graft resorption
  • Combined revision
    • femoral head and polyethylene exchange
      • indications
        • eccentric wear of the polyethylene with stable acetabular and femoral components
      • outcomes
        • hip instability is the most common complication of isolated liner exchange
    • conversion from a hip arthrodesis
      • indications
        • low back and knee pain as a result of arthrodesis
      • outcomes
        • implant survival greater than 95% at 10 years
        • competence of gluteal musculature is predictive of ambulatory success
Surgical Techniques
  • Femoreal revision with uncemented extensively porous-coated long stem prosthesis
    • technique
      • femoral stem must bypass most distal defect by 2 cortical diameters
        • prevents bending moment through cortical hole
      • cavitary lesions are grafted with particulate graft
      • allograft cortical struts may be used to reinforce cortical defects
  • Femoral impaction bone grafting
    • technique
      • morselized fresh frozen allograft packed into canal
      • smooth tapered stem cemented into allograft
  • Acetabular revision with porous-coated hemisphere cup with screws
    • technique
      • cavitary lesions are filled with particulate graft
      • cup placement should be inferior and medial
        • lowers joint reactive forces
      • metallic wedge augmentation may be used if cup in good position and rigid internal fixation is achieved
      • jumbo cups may be used when larger reamer is needed to make cortical contact
      • structural allografts may be used to provide stability while bone grows into cementless cup
  • Acetabular revision with reconstruction cage with structural bone allograft
    • technique
      • polyethylene cup is cemented into reconstruction cage
      • bone graft placed behind cage
  • Femoral head and polyethylene exchange
    • technique
      • exchange both head and liner
      • osteolytic defects may be bone grafted through screw holes to fill bony defects



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[Following is a quiz with 5 questions.  I thought it was useful to look at this because it gives you a sense for what the surgeon has to figure out when a patient walks in the door with symptoms.  The options are numerous but the right answers are few.  I can just imagine  how difficult it must be for a surgeon attempting to address a problem like MOM hip implants with no real clinical data to go on.  As my surgeon said several years ago:  "Its  all very  murky."  He just didn't know what to do which is why I sought out some consultants who were very familiar with the issues surrounding this problem...which several years ago were few and far between.

This quiz is not about MoM hips so skip this section if the thought process involved in getting to an answer is not of interest to you. The pictures accompanying the commentary are interesting too!

Connie]