Hip Preservation Clinic

Total Hip Arthroplasty

Replacing an Arthritic Hip Joint with Prosthetic Implants

Hip replacement surgery is for when hip preservation surgery is no longer, or not a good option for hip arthritis, hip dysplasia, or other end stage hip disease. It is performed either under general anesthesia or sedation with spinal analgesia depending on the health and safety of the patient first and foremost. 

The hip is a ball and socket joint lined with articular cartilage, which is a smooth, minimal friction interface which allows for a wide arc of motion of the lower extremity, and stable high impact weight bearing. When the cartilage is lost as a result of progressive arthritis, the hip joint degenerates, causing both the femoral head (ball) and the acetabulum (socket) to change shape in such a way that leads to loss of motion, pain with activity, and pain at rest. When hip preservation, nonoperative interventions such as injections, lifestyle modifications, and other conservative treatment strategies no longer help, hip replacement surgery offers long term relief. 

Hip replacement surgery will remove the arthritic joint in entirety with specialized instruments and replaces the native, diseased hip joint with new prosthetics which will either integrate into the native bone, or will be fixed with bone cement if the bone is weak or brittle. Acetabular implants (cup) are most frequently made out of a porous metal (in the United States) which allows the bone to grow into it ideally for permanent fixation. This is then lined with an ultra high molecular weight crosslinked polyethylene (surgical grade plastic) liner. The femoral component is typically a wedge, tapered design which is seated into the top of the femur after the head and part of the neck has been removed, and sized to fit the patient’s native anatomy if appropriate. 

Before hip replacement - the joint space is almost completely gone on the right side.
After Hip Replacement

Sometimes cement is necessary to fix the femoral component to the femur if the bone is at risk of fracture during the surgery. For patients with soft or osteoporotic bone, cement fixation is often a safer option than “press fit” implants. 

The native head (ball) is replaced with either a metal or ceramic head, which sits perfectly in the plastic liner. The goal of this is to provide long lasting improved function, and pain relief in patients with end stage hip disease. 

Hip replacement implants come from different manufacturers, and have different designs similar to makes and models of cars. Although hip replacement surgery is one of the most common elective procedures performed, it is not a one size fits all surgery. Therefore, different patients will require different “makes and models” of their implants depending on their anatomy (underlying hip dysplasia, excessive femoral antetorsion to name a few), bone strength, metal sensitivity, spine disease, dislocation risk(s)). Your surgeon will pick the implant(s) based off of these considerations, and preference for implant system(s). 

Robotic Assisted Surgery

Your surgeon may use a robot to assist with parts of the surgery. For hip replacement surgery, the robot is used for precise bone resection usually on the socket side, and for accurate placement of the acetabular component (socket). The use of a robot requires advanced imaging such as a CT scan done at least two weeks prior to the scheduled surgery. This allows the surgeon to create a personalized plan for your surgery and template the position of your implants based on your own anatomy before you even go to the operating room! You can think of the robot as a stable “extra arm” that the surgeon uses to make the surgery easier, and more accurate. Using the robot can also decrease the number of x rays needed to ensure precise placement of components.

Minimally Invasive Surgery

Although minimally invasive joint replacement surgery sounds like less surgery, it is actually the same amount of surgery through a smaller incision. This is not always an appropriate option for everyone as the primary objective is to perform an effective surgery safely and efficiently. Although there are benefits to minimally invasive surgeries such as smaller scars, less pain early on, and possibly some muscle sparing, these things are not as important as making sure the joint replacement goes in correctly. The biggest obstacle to a minimally invasive approach is body size, weight and habitus. If minimally invasive surgery does not work for your body type, the surgeon will choose the safest incision for your body to ensure a successful joint replacement surgery.

Direct Superior Approach

When this is an option for your body type, the direct superior approach is a muscle splitting approach, which creates a mobile window to the hip joint. The proposed benefits of this approach are decreased blood loss, faster recovery, sparing of a structure called the Iliotibial (IT) band, and sometimes the piriformis muscle. This is proposed to increase soft tissue stability following joint replacement surgery, and therefore helps mitigate prosthetic dislocation risk. No approach has a zero dislocation risk, and the direct superior approach is one of many. It does create a smaller incisional scar, which can easily be hidden with a conservative bikini bottom.

Preparing for Surgery

Prior to surgery, the team recommends the following:

  • Medical Assessment: your PCP will evaluate you to risk assess and stratify you for elective surgery. This may include a recommendation to see other specialty health care providers including but not limited to a cardiologist, pulmonologist, etc to ensure that it is safe for you to have hip replacement surgery.
  • Pre-Admission Testing will also call and evaluate you prior to surgery. They may require additional testing or consultation with other physicians to ensure that you are healthy enough to have surgery. Joint replacement surgery is considered MAJOR SURGERY, and so blood loss, nerve injury, loss of limb and life are all potential though minimal risks of surgery. Therefore it is important to make sure these risks are mitigated as much as possible to ensure the safest way(s) to proceed with surgery. 
  • Watch the total joint arthroplasty class video or attend a total joint arthroplasty class: This is a combination of nursing and therapy care objectives to make it easier to understand how to live with a joint replacement directly after and for the first few months after surgery. This will include how to act and “not act” or the “do’s and don’ts” to make sure you avoid complications such as hip fracture and dislocation following surgery. 

If you have had a steroid injection into your hip or knee joint in the last 3 months, you will have to wait until at least 3 months following the injection for surgery. Steroid injections within a 3 month period prior to joint replacement surgery puts you at higher risk for prosthetic joint infection. 

  • Shower with the provided surgical scrub provided in the preoperative appointment. 
  • No active dental caries: Active dental disease represents low grade focal infections which puts you at risk of having a joint infection. If you have cavities or severe gum disease, you will have to see a dentist to get this treated prior to joint replacement surgery. If you have active dental disease, you will have to wait after dental treatment for 6-8 weeks to decrease the risk of infection. 
  • Laboratory panel: You will have to have a blood draw within 1 month of surgery to assess for biological markers such as Hba1c, albumin, creatinine etc to determine your risks in undergoing surgery. Depending on these tests, you may have to delay surgery until these lab values are optimized. 
  • Maintaining a balanced diet (including calcium and Vitamin D)
  • Cessation of nicotine and marijuana use (if applicable) You will be tested for nicotine use prior to surgery, and if above a risk assessed threshold, surgery will be delayed until your lab tests are within acceptable limits. 
  • Temporary cessation of food supplements that may affect coagulation process or bleeding.
  • Temporary cessation of Warfarin or other anticoagulants five days prior to surgery, in consultation with your prescribing physician
  • Temporary cessation of immunomodulator or immunosuppressive medications to decrease the risk of infection and improve wound healing. See linked chart if you are on these medications. You may have to consult with your prescribing physician as well to determine if this is safe to do. 
  • Maintain cardiovascular fitness and strength as able prior to surgery. I recommend isometric exercises as this does not require motion of the joint as well as non/low weight bearing activities such as cycling, modified yoga/pilates, and swimming. 
  • Identifying a trusted person to help take care of you after your hospital discharge and assist in the first 7-10 days after surgery when energy level is low and mobilization is challenging or unsafe. 
  • Acquiring a walker (You will need to use the walker at all times for the first 2-6 weeks following surgery).
  • The hospital–BCH–will call to inform you of the time you should arrive at the hospital on the day of your surgery, and the time to begin fasting.

Dr. Lee adheres to these nationally and association recommended clinical practice guidelines recommended by the American Association of Hip and Knee Surgeons (AAHKS):

Post-Operative Instructions
& Rehab Protocols

At discharge you will receive a post op folder with instructions on how to care for your dressings and when you may bath or shower. We ask that you do not remove your dressings unless they are saturated or leaking. If you are unsure, please review our instructional videos and call if needed. The post op folder will also include your medication instructions, a Persons With Disabilities parking privileges application and your hip arthroscopy photos. There is a pain/medication tracking sheet you will be asked to fill out and bring to the first post op appointment. A hip preservation team contact list will also be provided; use this to reach out with urgent matters.

"Dr. Mei-Dan did PAO operations on both of my hips when I was in high school. Thanks to him and his team, I've been able to come back from my injuries to compete in college soccer. Thank you to Dr. Mei-Dan for bringing me this far!"
– Evan Toth (PAO)