Anterior Hip Replacement is a different philosophy for performing a total hip replacement compared to traditional hip replacement surgery for advanced osteoarthtritis.
Historically hip replacement surgery was via Posterior or Lateral (side) approaches. To access the hip joint via these traditional approaches requires certain muscles or tendons to be cut.
The anterior hip replacement approach to the hip joint goes between anatomically different muscle and nerve planes to the front of the hip joint. Muscles and tendons are respected and not cut for exposure of the joint.
Benefits of Anterior Hip Replacement include:
Prevention of limping: Anterior hip replacement protects the various muscles, blood vessels and nerves encountered during exposure of the hip joint. Minimizing muscle and nerve damage reduces the chances of limping.
Decreased post-operative pain: In comparison with “traditional” surgical techniques patients report reduced post-operative pain.
Reduced risk of dislocation (separation of the hip ball and socket): By preserving the muscles around the hip, the stability of the hip is improved. The risk of dislocation is minimal and the post-operative limitation of movements, usually prescribed in other techniques, is not necessary. The risk of dislocation is reduced because the Anterior Hip Replacement technique is performed from the front of your body and dislocation is often related to posterior hip structure damage.
Small skin scar: The skin incision is often shorter than traditional surgery and resulting scar tissue is reduced.
Shorter hospital stay. Many patients can go home 2-3 days after the operation with minimal pain and walking comfortably.
Less blood loss: Preservation of muscles and vessels potentially reduces blood loss and transfusions are rare.
Quicker rehabilitation: Rehabilitation begins immediately following the operation Once the spinal anaesthetic has worn off standing up and walking with arm-crutches or a walker can begin. Blood clots in the legs (deep venous thrombosis) and lung fluid collections are potentially less likely due to the increased mobility.
Faster return to daily activities: The Anterior Hip Replacement technique allows you to return to daily activities in a short time frame. You may drive when able to get in and out of the car comfortably, have excellent control of your legs and are not taking pain medications. Depending on your general condition, you may be driving in 8-10 days.
Animation of Anterior Hip Replacement
An anterior hip replacement can be technically more challenging with special instruments and a custom operating table required to perform the surgery.
The Anterior Hip Replacement is not suitable for all patients. For patients who have hip deformities from childhood that require the femur to be surgically shortened or require revision of the femoral prostheses I often use the more traditional approaches for greater access.
Patient Specific Anterior Total Hip Replacement
Accuracy of implant positioning and sizing can be improved by using 3D CT preoperative virtual planning. This can halve the risk of malalignment compared to using 2D Plain Xrays alone for templating .
Virtual planning allows 3D printing of Patient-specific guides along with life sized models of both pelvis and femur with the planned prosthesis inserted. These models are sterilised and used during to the operation. During the operation X Rays are taken when the implants are inserted to confirm accuracy with the preoperative virtual planning.
Download Information on Patient Specific Anterior Total Hip Replacement
The “bearing” is the area where the two moving parts of the anterior hip replacement are in contact and create a movable joint. There has been much interest in the media about particular surface bearings.
There are three main bearing materials which are divided into soft – polyethylene (plastic) or hard – metal or ceramic. No one material or combination is best for all patients and medical conditions. Each material has distinct advantages and disadvantages
Ultra High Molecular Weight Polyethylene (UHMWPE)
Benefits – Durable and versatile, long successful clinical history, non toxic
Limitations – Will wear down over time depending on activity level which can lead to inflammation, bone & tissue loss and/or revision procedure.
Benefits – Low wear rate which enables use of a larger femoral head which lowers risk of dislocation
Limitations – Higher revision rate compared to other bearings in joint registries, risk of adverse reaction to metal wear debris, unknown long term affect of raised metal ions in the body.
Benefits – Very low wear, wear particles inert, larger femoral head option to decrease risk of dislocation. Commonly used in young active people undergoing anterior total hip replacement.
Limitations – Risk of fracture, less forgiving in surgery, more expensive
Combination of materials
Hard on Soft – Hard femoral head (Metal or Ceramic) with a soft polyethylene liner. This is the most commonly used combination in Australia.
Hard on Hard – Metal on Metal or Ceramic on Ceramic. Ceramic on ceramic is regularly used in Australia according to the Australian Joint Registry. Metal on Metal has been found to have an increased revision rate. Some metal on metal implants have been withdrawn from the market due to unacceptable failure rates. As a result the use of metal on metal has significantly decreased.
Managing Arthritic Pain and relationship to changes seen on XR
Cartilage degeneration, although fundamental to the progression of osteoarthritis, is not the site of origin of pain. Peripheral nerves generally follow the path of blood vessels, and cartilage contains no nerves or blood vessels. Pain may be from the joint capsule , synovium (lining of capsule which produces fluid) , ligaments or bone as well as in the muscles and soft tissues, which surround and move the joint.
Plain radiographs show the effect of degeneration of joint cartilage as narrowing of the space between the surfaces of the articular bone (usually called the “joint space” or, more accurately, the “cartilage space”). However, it is possible to have considerable pain despite a normal-looking cartilage space, or pain can be mild despite marked narrowing.
Common radiographic changes often seen and reported in osteoarthritis are thickening of the subchondral bone (sclerosis) and formation of bone spurs (osteophytes) often do not correlate with the presence or the severity of pain. It is important to optimise a conservative management program before considering surgery.
Optimising Conservative Management
Before considering surgery it is important to have exhausted and optimised all non-surgical interventions as well as improving general health. Your physiotherapist and GP can help with this.
A good place to start and an excellent source of advice is Musculoskeletal Australia.
The effort and time put into conservative management even if it fails is not lost. This should be considered “Pre-Rehabilitation” and ensures that on the day of surgery you are as fit and healthy as possible. It ensures recovery as rapid as possible and improves the chances of an excellent outcome.
Dental treatment after anterior hip replacement
It has been common practise in Australia and Internationally to give patients after an anterior hip replacement or any type of joint replacement antibiotics prior to dental treatments to decrease the risk of infection of the joint replacement.
Most antibiotic coverage is not evidence based but rather anecdotal, historical or medico-legally based. The decision to cover with antibiotics needs to be individually assessed relative to both the health of the patient and the dental procedure being performed.
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