Thursday, February 16, 2017

Failed fixation of hip fracture with subsequent conversion to hemiarthroplasty

Hip Nail Failure Case

This case involves an elderly female who fell at home and fractured her hip. She was evaluated with x-rays and found to have an intertrochanteric hip fracture. Here are the initial x-rays:

I consider this fracture pattern to be unstable due to the reverse obliquity of the fracture line. The patient was optimized and underwent intramedullary fixation with a cephalomedullary device (Zimmer Natural Nail). Here are the intra-operative fluoroscopy images.

As seen above, the cephalomedullary nail is in excellent position and the fracture is well reduced and aligned. Here are x-rays taken at routine follow up evaluations:

Here are x-rays at a later date:

You can see evidence of screw migration and fixation failure. At this point the patient had severe symptoms. A CT of the hip was obtained. Here are the coronal and sagittal reconstructions:

As seen, the hip screw has penetrated the femoral head and failed. There is a nonunion of the fracture as well. This patient required additional surgical treatment. Removal of the hip nail and placement of a partial hip replacement or hemiarthroplasty was recommended. Revision fixation was not considered advisable due to damage to the head and high risk of failure.

Here are the final x-rays showing the long stemmed partial hip replacement. The Zimmer/Biomet Arcos Modular Femoral Revision system was used.

The patient recovered well from the surgery and has regained functional abilities. I have noticed a higher incidence of these kinds of failures over the last few years. I suspect it is related to an aging population with more severe osteoporosis. Nevertheless, I think there is room for improvement in implant design to improve the success rate.

Wednesday, June 22, 2016

Periprostheric femur fracture - Revision and ORIF

This is a complex hip fracture case. An elderly lady had a hip replacement a few years ago. Here are her post-op x-rays.
She did well after the surgery until she fell a few years later.
This is what the x-rays look like.

As you can see in the x-rays, there is a fracture of the femur around the hip implant. This is called a periprosthetic femur fracture. There are multiple fracture fragments around the proximal femur. The hip stem seems to have come out of the femur through the fracture and is no longer attached to the femur.
The best treatment for this type of problem is to remove the femoral component of the hip replacement and place a new, longer one and to fix the fracture with cables. This is called revision hip arthroplasty(replacement) with open reduction and internal fixation(ORIF).
The Biomet Arcos Modular Femoral Revision System was used for this surgery. The Arcos is assembled with different sized parts inside the femur during the surgery. It allows the surgeon to customize the implant for the specific surgical application.
Biomet Arcos(c)
Here is a x-ray showing successful revision of the femoral implant and cerclage cable fixation of the femur fracture.

Wednesday, February 19, 2014

What type of hip replacement implants do I use?

I get asked this question all the time by my patients. "What type of hip replacement do you use?"

This is an important consideration. There are many companies that make implants for hip replacement surgery and each company has multiple product lines. It is alot like automobiles. You could get a Ford or a Honda (the company) and within each company you could get different models (like the Ford Taurus or the Honda Civic).

Each company has a historical track record and each model (as long as its been out for a few years) will have outcomes and performance data that could be used to make a decision on which one to choose.

Other considerations are patient specific. For example a young active patient might do better with an implant designed to last a long time while an older disabled patient might need an implant that provides maximum stability. Different implant designs may be optimally suited to different bone types and anatomical variations.

Just like there are Ford guys and Chevy guys, you will find surgeons who are Zimmer guys/girls, Stryker guys/girls, etc. There is a comfort level with the implants and instrumentation that is necessary in order to achieve optimal results that are consistent. It is not advisable to constantly change implant types.

The bottom line is that most surgeons use one implant design for the majority of patients and have others that they use as back-ups for atypical cases.

For the majority of my hip replacements I use the Zimmer Alloclassic® or Zimmer® M/L Taper Hip Stem. These stems both have excellent track records with almost 100% success rate in research studies. For information on the stems click on the links:
Zimmer Alloclassic®
 Zimmer® M/L Taper Hip Stem
For the socket or cup, I usually use the Zimmer Continuum® Acetabular System. The cup is made with trabecular metal which achieves an excellent press-fit into the socket bone and has immediate stability. It also has an excellent track record.For more information, click on the links.
 Zimmer Continuum® Acetabular System
The last part of a hip replacement is the bearing surface. The bearing surface is referring to what parts are gliding on one another when the joint moves. There are a few options such as metal on poly, metal on metal, ceramic on poly, and ceramic on ceramic. The picture above shows a pink ceramic ball which is the Biolox® Delta Ceramic Femoral Head. This is a very strong, hard, and smooth design that achieves optimal longevity and durability.

Take a look at a golf pro try to break one with a driver. The driver gets dented and the head is fine!

I use the ceramic head with a Longevity® Highly Crosslinked Polyethylene Liner. Click on the link below for more details.
Longevity® Highly Crosslinked Polyethylene Liner

 This combination is selected to achieve the best results for my patients as far as longevity, durability, and stability. I could go on and on about this and this may be too much information for most patients. If you have any questions please ask me.

Wednesday, October 23, 2013

Direct Anterior Hip Replacement - Dr. Nasar

I recently performed a direct anterior hip replacement. This is a new approach to hip replacement that preserves the muscles. It usually allows very rapid return of function and patients do not have to worry about dislocation. They can bend over right after surgery without a problem.
Anatomy of the Hip Joint
By Smith & Nephew (Smith & Nephew) [FAL], via Wikimedia Commons

The direct anterior approach uses a small (4") incision in front of the hip. This approach is known for a pain free recovery.

Thursday, October 17, 2013

Severely Bowed Knee - Complex Knee Replacent with LCCK & Stems

I have come across a few patients recently where their knee arthritis was so severe and has gone on so long that their legs have become severely deformed. In these cases, standard knee replacement implants will not work properly. The ligaments that hold the knee in place can get stretched out in severe cases and when the deformity is corrected and the leg is straightened, the ligaments become incompetent.
In these cases, a constrained type of knee replacement implant must be used. Constrained implants have larger internal supports that hold the implant together and have stems or rods that anchor the implants deep within the bone so that they can absorb the increased forces necessary to hold the knee together. I personally use the Zimmer NexGen LCCK system for these cases.

Here are before and after radiographs (x-rays) of a recent case:
Severely bowed knee with advanced arthritis
Post-operative x-ray showing knee replacement with constrained LCCK implants. 
As you can see in the second set of x-rays, the angulation (deformity) has been corrected with this stemmed implant. It has been one month since surgery and he is doing exceedingly well.

Sunday, June 9, 2013

Facebook Groups for Hip Replacement NJ and Knee Replacement NJ

I recently created Facebook groups for patients who are interested in hip and knee replacement surgery to join and share information with each other and to ask questions about surgery and the recovery process.

·         Knee Replacement:
·         Hip Replacement:

Feel free to join and share.

Friday, May 3, 2013

How are Hip Implants attached to Bone? Do you use Glue?

The bonding of hip joint replacement parts to bone is very important to the success of the surgery. Patients are often interested in how this is accomplished. This topic has been highly researched in orthopedic journals for many years. Historically, bone cement (poly methyl methacrylate) was used to glue the parts of hip implants to bone.
Methyl-methacrylate By Jynto and Ben Mills [Public domain], via Wikimedia Commons

In general, bone cement is very successful when used as a bonding agent. It needs to be properly prepared and pressurized into the bone and it works well. More recently, researchers have concluded that bone cement can break down over time in active patients. At the same time, orthopedic engineers have designed implants that have a roughened surface that bonds directly to bone without the use of cement. As a result, the orthopedic community has gradually shifted to the use of cement-less,  porous coated implants for hip replacement.
Both the cup and the stem are usually implanted in what we call a "press-fit" manner. That means that the prosthesis is just a little bit larger than the opening in the bone. When the implants are impacted into position, they jam into place and have enough roughness and surface friction that they stay in place and are immediately stable. Usually a patient can put their full weight on the hip immediately after surgery without concern for the implants coming loose. Here is a hip replacement x-ray.

X-ray showing a total hip implant placed without cement or screws. Note that the metallic prosthesis is in direct contact with the bone.
Next I will cover the use of bone cement for knee replacement.