This is a transcript of a
Live Chat in the Surface Hippy Chat Room with Dr. Mont on July 30, 2008
Dr. Mont will answer questions about your specific
hip problem if you send him your information and x-rays. You can
email him at Rhondamont@aol.com
You must include your phone number because he
prefers to talk to you via phone.
You can also call his office at (410) 601-8500. Ask for Terri, Colleen, Jean, or Jill.
He will be happy to call you if you send x-rays and a brief history.Welcome to our Chat with Dr. Mont.
Dr. Mont has done over 1600 Hip Resurfacings and is from Baltimore MD
Dr. Mont 8:01 pm: I want to thank Pat for her efforts on this site and for her tremendous efforts aimed at helping fellow patients. Thank you for giving me this opportunity to share my thought with your audience.
[Pat Walter Monitor] Could you tell us how long your have done hip resurfacing
Dr. Mont 8:02 pm: I started limited resurfacing of femoral head only in 1989, for
a disease called avascular necrosis or osteonecrosis. I began full metal-on-metal resurfacing in 2000. The United States MOM resurfacing resurfacing experience started in 2000 at 7 centers.
[Pat Walter Monitor] 8:03 pm: What hip resurfacing devices do your normally use?
Dr. Mont 8:03 pm: I use multiple devices; Conserve Plus, BHR, and Cormet. I use all of the devices
- they are similar but each has subtle differences in fixation surfaces, etc.
Dr. Mont 8:04 pm: alternatives: non-operative vs. operative is first decision tree
if you have a bad hip
[gimpy1] 8:05 pm: I am looking at a steroid shot as the first step.
Dr. Mont 8:06 pm: Start with meds, activity restrictions, exercise, weight loss, typically even before steroid injections.
[Pat Walter Monitor] 8:06 pm: I had a question today - the man wanted to know how heavy of a load he could lift after resurfacing? Also how long he would wait until he could lift the full weight
he normally did?
Dr. Mont 8:07 pm: It is difficult to give you an exact answer. Obviously, this varies from person to person. Typically, surgeons do not recommend lifting greater than 20-30 pounds on a regular basis after any hip replacement. This is because the extra force on the hip is believed to accelerate wear of the prostheses which could lead to premature failure of the device. However, no one really knows the answers to the question of what is too much weight that leads to accelerated wear.
Dr. Mont 8:09 pm: I do believe that if one wants to regularly lift greater than 30 pounds or participate in high impact activities, then they should regularly keep their hip muscles strong. I know from a study we did that at least 30% of patients will participate in these activities despite surgeon advice to the contrary. Therefore, keep your hip muscles strong to protect your prosthesis!!
Dr. Mont 8:07 pm: I usually tell patients that completely sedentary activities will probably afford the best chances of devices lasting 20 years or longer and that patients that do heavy lifting or other high impact activities may lead to prosthetic survival of less than ten years
- I have two patients that run marathons yearly. There is a difference in what patients are capable of doing and what they should do. The exercises I advocate encompass 20 minutes every other day—about an hour per week to specifically strengthen your hip.Dr. Mont 8:09 pm: If one is going to lift, it should be done when the hip muscles are back to close to normal in strength. I advocate getting ankle weights and achieving a certain level of hip strength before lifting.
Also remember that there is a difference between simply lifting something without walking in which case the 50 pound weight is distributed to both hips and effectively is 25 pounds of force on each hip. Not so bad. If you lift and then walk with the object then the 50 pounds that one is caring
is on one hip at a time.
[dc] 8:07 pm: Dr. Mont, I just learned that I need a hip replacement. I saw a surgeon today and he recommended a THR with an ASR-XL system. He said the he prefers the THR approach because there is evidence for a 1%/year
failure rate for the femoral cap on resurfaced hips vs a 1%/10 year failure rate for THRs.
Dr. Mont 8:08 pm: Failure rates early in learning curve were high for resurfacing but now approach and are even superior in some patient populations---young, active, males
[stevel] 8:09 pm: I was on your previous chat 7/16. Thanks for evaluating my x-rays and I need to call you as I could be a candidate for resurfacing. Will you know if I can be resurfaced and how often do you switch to a hip replacement if defects are found during the resurfacing operation.
Dr. Mont 8:11 pm: In your case--less than 1% though this should be continued off-line
- I've switched to a total hip replacement about 20 times out of 1650 though more than half
I knew were difficult going in.
Dr. Mont 8:11 pm: My phone number at the office is (410) 601-8500. Ask for Terri, Colleen, Jean, or Jill. I will be happy to call you if you send x-rays and a brief history.
Dr. Mont 8:12 pm: For various reasons, my answers have to be generic and not targeted to a specific patient.
[Pat Walter Monitor] 8:13 pm: Many people ask doctors if the preserve the neck capsule. Do you and why or why not?
Dr. Mont 8:16 pm: I don't preserve the capsule as the anteriorlateral approach that I use doesn't lead to dislocations. If you preserve the capsule it can grow larger and lead to stiffness and decrease range-of motion. For posterior approaches where there is a higher dislocation rate many surgeons repair the capsule to keep hip stiffer.
[Pat Walter Monitor] 8:16 pm: Could you tell us a little more about the anterior approach and why you prefer it?
Dr. Mont 8:17 pm: The choice of approach to use for resurfacing has received much attention and I believe extra “hype.” In multiple studies now published, there are no reported clinical differences in the short term and up to ten years of follow-up between anterior and posterior approaches. I believe that any approach can be used and the surgeon should use what they feel most comfortable.
Dr. Mont 8:18 pm: Short-term differences that patients may report with either approach have to do with other factors in my opinion. I use the antero-lateral approach because it affords me easy exposure, lower dislocation risk, less chance to disrupt the blood supply of the femoral head
- among other reasons. However, I have no problem with posterior approaches and am currently working on an even more minimally invasive anterior approach.
[dc] 8:18 pm: Dr Mont.--I am a 45 year old male who is a fit 5' 10" and 210. I have psoriatic arthritis and it appears to have lead to my hip degeneration. I have been told my two different surgeons that I need a hip replacement. However, I am on a remicade and leflunomide for my psoritatic arthritis. I get a large dose of remicade monthly. I am wondering if the trauma from the surgery has a chance of starting a flare of my PA? How do you deal with patients who are on remicade who need hip surgery-Thanks
Dr. Mont 8:19 pm: Patients with inflammatory arthritis which you have are not always the best candidates for resurfacing. That's because the bone is generally weaker. Psoriatic arthritis though needs to be evaluated on a case by case basis.
Dr. Mont 8:21 pm: Any surgery or trauma can lead to a flare up though this can be controlled so typically patients just need to be monitored if they are getting any surgery.
[nzuk] 8:21 pm: Can you recommend a Doctor in Massachusetts?
Dr. Mont 8:21 pm: What type of doctor? lol
Dr. Mont 8:22 pm: I'm not familiar with too many surgeons doing resurfacing in Massachusetts though I can research it for you later
[stevel] 8:23 pm: My health insurance will pay for a hip resurfacing device approved for marketing by the FDA. Only Birmingham and Cormet qualify. If I selected Birmingham, will you install it or and how do you decide which device to use?
[dc] 8:24 pm: That is good to know about PA- I agree that patients with PA may have weaker bone as I learned today that the head of my femur has a flat spot on it and may be cracked.
Dr. Mont 8:24 pm: I would install a Birmingham or Cormet depending on patient preference. Sometimes the choice of device is limited by patient size as Cormet doesn't have smaller sizes.
Dr. Mont 8:25 pm: I'd be happy to look at your x-ray if you email it to me at Rhondamont@aol.com
[email@example.com] 8:25 pm: What are the risks if one hip has osteopenia? It's the one I am doing first. My surgeon Dr. Scott Cook (Kansas City) thinks I will be fine (OA) although mentioned that I could be at a little bit greater risk for femur fracture. He said yesterday that my xrays show a straight forward BHR. I am small: 5'4 and 104 lbs.
Dr. Mont 8:26 pm: For various reasons, my answers have to be generic and not targeted to a specific patient. I can answer questions very specifically if you don’t personalize them.
[Pat Walter Monitor] 8:27 pm: Could you explain what osteopenia is.
Dr. Mont 8:27 pm: If one has true osteopenia one should not be getting a resurfacing. There is a higher risk of femoral neck fracture.
Dr. Mont 8:29 pm: Osteopenia is a term for bone loss that can arise from many conditions: osteoporosis (what you get as you age), disuse osteopenia (if you don't walk on you hip), osteomalacia--Vitamin D disorder--get your sunshine--all have varying degrees of bone loss.
[firstname.lastname@example.org] 8:29 pm: What risks are involved with smaller boned women?
[Pat Walter Monitor] 8:30 pm: Does the size of the pin on the cap device cause a problem in small boned women?
[stevel] 8:30 pm: You looked at my x-rays I sent on 7/21. I need to call you to discuss as I could be a candidate for hip resurfacing. Do you test for metal allergies?
Dr. Mont 8:30 pm: Small boned women have thinner necks and could be more susceptible to femoral neck fractures.
[Pat Walter Monitor] 8:31 pm: Is the pin size for all BHR devices the same? I heard that?
Dr. Mont 8:31 pm: For example a women with bone half the diameter of a man which is common will have one eighth of the bending strength or only 12.5% of that man.
Dr. Mont 8:32 pm: I test for metal allergies in patients with a history of allergy to metals.
[jaredmanders] 8:32 pm: Any thoughts about two opposing actions recommended by doctors? 1. if you are looking for a THR most docs ask you to wait as long as you can. 2. If you are looking for BHR, it appears that if you wait to long, it could be a problem. Most doc in this case would tell you to get the procedure as soon as you can so one does not cause any more damage?
Dr. Mont 8:32 pm: First of all, one has to know what you are allergic to. Nickel allergies are probably ok since resurfacings have minimal to no nickel, but you should be tested for cobalt and chromium before a metal-on-metal device if one has a metal allergy. Traditional skin testing for allergies are not great--there are blood tests at specialized labs that do better tests though this is a field that still needs more research. Four to five labs will do the blood tests from around the country.
[dc] 8:33 pm: Dr. Mont- Thanks for the information. What type of data do you use for evaluating bone strength prior to a hip resurfacing?
Dr. Mont 8:33 pm: Not sure what you mean by pin size--in case yes--they are similar and not really relevant in my opinion
[Pat Walter Monitor] 8:34 pm: I mean the size of the post with cap. I heard some doctors use the ASR for really small women since their neck is smaller.
Dr. Mont 8:34 pm: Jared - to some extent correct. But you shouldn't rush into a resurfacing if you don't need it.
[email@example.com] 8:34 pm: Sorry if this is a dumb question:does the femoral fracture in small women occur after surgery due to a fall or accident or does this occur in surgery?
Dr. Mont 8:35 pm: I think you may be confusing extremes - some people wait way too long
- till their practically wheel-chair bound and then they want a resurfacing and find out its too late.
[jaredmanders] 8:36 pm: I'm worried about waiting too long. I was diagnosed 3 years ago. I'm ready for it now psychologically and physically. Did I cause damage by waiting? I'm able to walk basically with very little limp at this stage but I do feel pain each day.
Dr. Mont 8:37 pm: I look at X-rays to initially check bone quality. some docs get DEXA scans but I don't. After the x-ray, my assessments are made intra-operatively to check strength and quality of bone.
Dr. Mont 8:38 pm: Pat --I'm not sure about that - post is probably irrelevant
- these devices would do fine without posts in most cases - don't think that any one company has monopoly on small women
- many can deal with small size issues.
Dr. Mont 8:40 pm: Femoral fractures we are talking about occur after surgery. If they happened during surgery which is quite rare then the patient would get a standard total hip replacement and not even be discussing a resurfacing fracture.
[firstname.lastname@example.org] 8:41 pm: Are small women at risk for femoral fractures from the surgery date and then on forever?
Dr. Mont 8:41 pm: Jared - again your personalizing and I can't give answers unless
I review x-rays, etc. You can call my office: My phone number at the office is (410) 601-8500. Ask for Terri, Colleen, Jean, or Jill. I will be happy to call you if you send x-rays and a brief history.
[Pat Walter Monitor] 8:42 pm: Can the improper placement of the cap and cup - as far as the proper angles, etc - cause a fracture at a later date because of unusual stresses to the bone?
Dr. Mont 8:44 pm: small women at risk initially mostly in 1st year. Then risk probably lowers though we don't know what happens later on with longer follow-up as some women become post-menopausal and lose bone stock and are more susceptible to femoral neck fractures then men as they get older.
[stevel] 8:44 pm: A lot of hype about athletes, impact sports and hip resurfacing. Have these devices lasted at least 10 years for such athletes?
[jaredmanders] 8:44 pm: I'm impressed with your availability. Thank you and I will take you up on the offer soon. Generally though, is there a ballpark time frame that is safe for BHR once diagnosis takes place?
Dr. Mont 8:45 pm: Improper placement can make one more susceptible to a later fracture.
Dr. Mont 8:46 pm: We don't yet know the long term effects of these sports (past 7 years) but I encourage patients to regularly exercise their hip muscles to unload the joint if they are going to participate. The best sports in my opinion are less impact
- swimming, bicycling, elliptical - these are probably fine - the higher impact sports are more likely to lower the lifespan of any implant. I don't encourage running but the patients do it anyway
- in one of our studies we found that 30% of patients returned to high impact
Dr. Mont 8:47 pm: The data is OK for about 7 years for the athletes - past that it's anyone's guess.
[email@example.com] 8:47 pm: So: Is BHR like a set of tires? We only have so many "miles" before the it wears out? In your opinion, does high impact exercise speed up the wear?
Dr. Mont 8:47 pm: BHR is a company device name - it should be referred to as "Resurfacing" since this a generic open discussion group.
[dc] 8:49 pm: What is the expected life span of an average hip resurfacing vs a total hip replacement?
[gimpy1] 8:49 pm: Does the device wear out or does the device wear the bone out with the high impact life?
Dr. Mont 8:50 pm: The time frame is quite variable - a hip can go in a short time only in rare cases less than one year (Rapidly progressive osteoarthritis)
- 3% or in cases of inflammatory arthritis. Many cases it is a gradual loss of bone. Many people that lose too much bone will feel a limb length discrepancy
- though this is all conjecture - a simple look at x-ray tells the story!
Dr. Mont 8:51 pm: tire analogy for resurfacing is generally correct - but we don't have all the answers
- see my earlier answer about wear.
Dr. Mont 8:53 pm: resurfacings have only been used for 8-9 years - doing well so we can't really guess or take this out to much past that
- they hopefully will last many years past that. Some standard total hip designs do great into their 15-20th year.
[jaredmanders] 8:53 pm: Here's a sensitive issue... What is the primary difference between doctors. If we shop for a car, we can use consumer reports etc. How do we judge a doctors ability, especially in America.
Dr. Mont 8:53 pm: device wears out - then will lead to wear of bone secondarily.
[stevel] 8:53 pm: Do you install full size metal hip replacements if hip resurfacing is not an option? Is this better than the traditional hip replacement (with a smaller femoral head)?
[Pat Walter Monitor] 8:54 pm: If you need to use a THR for a younger person, do you prefer a Metal on Metal or Ceramic on Ceramic.
Dr. Mont 8:54 pm: Some orthopaedic surgeons can do the procedure well after less than twenty cases
- others need more - This is a hard question to answer - It may have to do with the type of cases they are performing
- are they gaining experience with straightforward hips first and then advancing as they gain experience?
- which is correct way which is better than tackling hard cases too early
Dr. Mont 8:55 pm: I do large femoral heads if can't do resurfacing
Dr. Mont 8:56 pm: I prefer ceramic on polyethylene - avoids metal on metal issues and avoids possible squeaking issues
[firstname.lastname@example.org] 8:56 pm: Will the larger femoral heads help with range of motion? What are your restrictions if THR is needed?
Dr. Mont 8:57 pm: As a summary will list some advantages and disadvantages of resurfacing:
[jaredmanders] 8:57 pm: Why are all resurfacing procedures done with MOM. Why don't they make devices for this out of other materials?
Dr. Mont 8:57 pm: Large heads may help with range of motion - I give no restrictions with both procedures
[stevel] 8:58 pm: Ceramic on polyethlyene. This is a smaller head, correct?
Dr. Mont 8:58 pm: They are trying other materials but still experimental - at present would need too thick ceramics or other issues
- but in a few years maybe newer materials
Dr. Mont 8:59 pm: Smaller - but not that much smaller - can still use a 36-40 millimeter head! which is bigger than traditional 26-32mm
Dr. Mont 9:00 pm: Advantages of a resurfacing in my hands are (1) more range-of-motion, (2) less risk of dislocation, (3) more normal "feeling", (4) leaves options open for later conversion to standard THR, (5) Easy revision if necessaryt, (6) useful for certain deformities, (7) preservation of femoral bone stock
Disadvantages are (1) harder to do, (2) less follow-up--up to 10 years max, (3) risk of femoral neck fracture, (4) possible elevated metal ion in blood issues
[Pat Walter Monitor] 9:00 pm: Dr. Mont is available to discuss your hip problems if you send him an email with your x-rays and your phone number. He prefers to call you.
[Pat Walter Monitor] 8:59 pm: I want to Thank Dr. Mont for taking time to answer all our questions.
Dr. Mont 9:01 pm: Thank you Pat !!!!!