There are 2 broad categories of arthritis- Non-Inflammatory and Inflammatory.
Non-inflammatory arthritis is the more common type and is commonly referred to as osteoarthritis. Osteoarthritis is also known as ‘wear and tear’ arthritis since it occurs on the basis of repetitive stress and time. Osteoarthritis is the type associated with aging joints however many young people can also develop this condition within the context of predisposing circumstances, ie. Obesity, mal-alignment, genetic predisposition, trauma, sports etc. In addition severe trauma may cause post-traumatic arthritis which also falls into the category of osteoarthritis.
Inflammatory arthritis is the less common type. This arthritis is present in conjuction with another medical condition(s) such ass the autoimmune diseases- rheumatoid arthritis, systemic lupus erythematosis, psoriasis, ulcerative colitis etc. The common factor underlying the development of arthritis in these conditions is an autoimmune response wherebye the immune system attacks the persons own tissue and in the case of arthritis the joints are affected.
Osteoarthrtis and Inflammatory arthritis are generally easy to distinguish from each other based on history, clinical findings and radiographic/MRI imaging. Blood tests are also useful to diagnose or profile the autoimmune/inflammatory disorder. There can be a mix of the 2 conditions in some cases. When this occurs treatment pathways tend to favor the inflammatory vrs the non-inflammatory condition.
The symptoms of osteoarthritis include joint pain,swelling, stiffness, weakness, giving away. Limping,
With more cartilage loss there is by definition a higher severity level of the disease which is often associated with a greater level of symptoms and disability. When early pathway interventions are deemed ineffective the surgical pathway for long term resolution of symptoms is hip arthroplasty- total hip replacement or hip resurfacing.
Total Hip Replacement: This procedure involves the surgical implantation of synthetic materials that are engineered to replace the ball and socket joint. The femoral head (ball) is replaced with an artificial substitute. This is achieved by removing the damages femoral head by making a surgical cut in the femoral neck (where the ball meets the main portion of the femur bone). With the femoral head removed the interior of the femur bone is prepared to accept a femoral implant which will assume a position inside the femur bone. This main portion of the femoral implant which is designed to bond with the skeleton has a terminal point which is engineered to mate with a femoral head. The femoral stem mated with the femoral head becomes the reconstructed proximal femur . To reconstruct the socket the labrum is removed and the interior of the socket is surgically prepared to accept a metal implant (acetabular shell). The acetabular shell is designed to bond to the pelvis. There is then a modular liner which is engaged into the shell and has a locking mechanism. The acetabular shell with the engaged liner is the reconstructed socket. The reconstructed joint- ball and socket – together is called a total hip replacement. There are many different manufactured brands of total hip replacement systems. They vary in terms of their engineering as it relates to shape of the implants, tolerance and size, materials and composition as well as skeletal preparation methods. The ‘bearing surface’ which is the interface between the ball and socket and relates to the materials used and size also is a point of variation. Cobalt chrome is a common metal alloy used to manufacture the femoral head and this can is often mated with a polyethylene acetabular insert. This interface of cobalt chrome and polyethylene becomes the bearing surface. Cobalt chrome paired with highly corsslinked polyethylene is a standard bearing. Other metals with less abrasive properties such as oxinium can be paired with a highly crosslinked plastic achieving better wear properties and potential improved durability of the bearing. Another type of bearing surface is ceramic. Ceramic surfaces can be paired together achieving a ‘hard on hard’ interface or can be paired with polyethylene. Ceramic femoral heads paired with a highly crosslinked polyethylene surface is a common ‘hybrid bearing’ which has beneficial features of ceramic with some potential disadvantages of ceramic eliminated by cross pairing it. Metal on metal is another type of bearing surface. This is also a ‘hard on hard’ bearing with some potential advantages of reduced wear however potential disadvantages related to metal ion generation and metal hypersensitivity. There are potential relative advantages and disadvantages of all hip systems compared to others and the proper selection of a hip implant system should take into account a variety of factors that are client centered.
Hip Resurfacing: This is an alternative method of hip joint arthroplasty. This procedure is distinguished from a total hip replacement based on the use of a resurfacing cap that covers the femoral head following preparation. This is different from total hip replacement where the femoral head is removed and replaced. The potential advantages of a resurfacing hip over a hip replacement relates to the preservation of the femoral head and architecture of the proximal femur in that it more closely resembles the natural structures following reconstruction. The sacrifice made with this procedure is the loss of options as it relates to bearing surface options. All hip resurfacings are performed with a metal implant to cover the femoral head paired with an all metal acetabular shell. This ‘metal on metal’ bearing surface has come under increasing scrutiny as a result of reported complications considered to be a direct result of this metal on metal articulation. The metal on metal bearing is reported to generate wear debris which is in the form of metal ions. These metal ions are deposited into the local tissues where they can incite a local immune response which is destructive to the host anatomy. In addition the metal ions enter the circulatory system and have been reported to cause a variety of potential problems including damage to the heart and liver. Based on these reports of complications related to hip resurfacing we do not offer this procedure at Regional Orthopedics. Our interpretation of the potential benefits is that they do not outweigh the potential risk for having serious complications. We believe that given the alternative treatment of hip replacement as a safe alternative with excellent reported outcomes the potential serious risk and complications associated with hip resurfacing are better off avoided.
Surgical Technique: There are a variety of different surgical approaches to hip replacement surgery. The posterior or ‘southern’ approach is a traditional approach to hip arthroplasty. This places the incision over the buttocks and lateral side of the hip. The size of the incision is variable and depends on a number of factors not least of which is the size of the patient. The approach uses natural muscle planes to reach the short external rotators which insert on the posterior aspect of the greater trochanter. These short rotators are then surgically taken off the bone to expose the posterior hip capsule which is then opened to access the joint . The benefits of this approach is that it affords excellent surgical exposure of the hip which is critical for achieving the critical goal of preparing the skeleton and placing the implants in proper alignment and orientation with appropriate sizing and tolerance to achieve skeletal union to the implant. Improperly aligned or incorrectly sized implants can lead to a poor outcome with early failure and revision. In addition this approach is extensile meaning that it can be easily extended to expose more the of the hip and femur if complications are encountered during the procedure such as femur or acetabular fracture. Also, in the event the implants require revision at any point in time the posterior approach is a typical approach for revision procedures whereby the same surgical incision and approach can be utilized. The location of the incision on the buttocks and side of the hip also allows for an easier recovery to the extent that sitting does not crease the incision and lying on the back or unaffected side also does not compress or stress the incision.
Anterior Approach: This is in contradistinction to the anterior approach to the hip. This is a recently popularized approach and is marketed as having the advantages of being an approach that facilitates a quicker recovery based on the ability to avoid fully releasing the short external rotators which are removed and repaired in the posterior approach. The studies currently published looking at this question seem to suggest that on average the recovery time of the anterior approach is accelerated in the first few weeks following the procedure however the benefit no longer exists by approximately 6 weeks. The potential disadvantages however are the location of the incision which because of its location over the front of the hip in the crease of the skin increases the potential for wound healing complications. In addition the vascular supply to the hip is largely from anterior vessels as branches of the femoral artery which is also in close proximitiy to the surgical dissections and these arterial branches can lead to excessive bleeding which has the potential to increase the risk of a variety of complications incluiding surgical site infection. This approach also is not extensile and and can present a problem if complications are encountered during the procedure and more visibility is required. In addition revision implants such as long femoral stems are not often able to be achieved through this approach necessitating an additional posterior surgical dissection if this was necessary at any point in time. At Regional Orthopedics we recommend the posterior approach as a safe and effective method for performing this procedure. We believe that the anterior approach to the hip, although it may offer an early advantage of quicker recovery , this benefit is absent by weeks 4-6 and this potential advantage is outweighed by the potential disadvantages associated with the approach.