Normal Anatomy of the Wrist
The wrist joint is a complex joint made up of many different bones, tendons, and ligaments. This is why the wrist joint has such a wide range of motion. The wrist joint is the connection between the bones of the hand (metacarpal bones) and the bones of the forearm (radius and ulna). The bones of the wrist are called carpal bones, and there are 8 of them. All of these bones work together with the muscles, tendons, and ligaments of the hand and arm to give you good strength and range of motion. In the areas where these bones touch each other, they are covered in cartilage (articular cartilage) which helps prevent excessive friction and protects the bones from stresses. When the bones, muscles, and other tissues are healthy, you have full function of the hand and wrist. However, sometimes things can go wrong, especially due to injury, disease, or wear and tear.
Injuries and Problems of the Wrist
When the wrist is injured, or there has been excessive wear and tear, the articular cartilage covering the bones can become thinned out, or even completely worn away, leading to bone on bone contact. When this happens the joint becomes inflamed and painful, and this is commonly known as osteoarthritis. In chronic inflammatory diseases such as rheumatoid arthritis, the joint surfaces can be damaged quite severely. There will be swelling, pain, stiffness, and even deformity of the wrist and hand. Sometimes, infections can cause damage to the joint surfaces in the wrist, leading to loss of function, pain, and arthritis. When these situations occur and other more conservative approaches to treating the pain and dysfunction have not helped, you may be a candidate for wrist replacement surgery.
Types of Surgical Interventions for the Wrist
Wrist joint fusion (Radiocarpal Arthrodesis)
This is still the most common surgical procedure for treating painful wrist arthritis and dysfunction. This surgical procedure involves fusion of the bones of the wrist in order to reduce or eliminate the pain and improve the strength in the hand. However, since this involves fusing the bones together, there will be a loss of range of motion, that is, the wrist will not be able to bend anymore. This may not be suitable or desirable for many people.
Wrist joint implants (Total Wrist Arthroplasty)
Wrist replacement surgery involves the use of implants to help restore function of the wrist joint. These implants are usually comprised of two metal components and a spacer. The metal components are fastened into the bones of the wrist and forearm, and the spacer is placed in between them. The metal components typically have two different shapes: one is curved and one has a flatter profile. The spacer fits between the metal components and helps create a smooth friction reducing surface for the implant to glide against allowing for a more natural wrist motion. The spacer comes in different sizes so that you get the best fit for your individual needs. Typically, the spacer will snap on to the metal implant that is on the hand side of the wrist, and it articulates with the cup shaped metal implant on the forearm side of the wrist. There are a variety of surgical implant technologies for wrist arthroplasty. These variations include different ways the implant is attached to the bones of the forearm and wrist, as well as differences in the composition of the spacers used in between the metal components.
This page is for information purposes only, and describes general information. You should always talk to your physician regarding specific details of your surgery.
References
https://orthoinfo.aaos.org/en/treatment/wrist-joint-replacement-wrist-arthroplasty/
Carlson, Jeffrey R. MD; Simmons, Barry P. MD, Total Wrist Arthroplasty, J Am Acad Orthop Surg 1998;6:308-315
Taljanovic MS, et. al., Joint Arthroplasties and Prostheses, RadioGraphics Vol. 23, No. 5 Published Online:Sep 1 2003 https://doi.org/10.1148/rg.235035059
Nair, R, Review Article: Total Wrist Arthroplasty, J Orthopaedic Surgery, 2014;22(3):399-405
This page is for information purposes only, and describes general information. You should always talk to your physician regarding specific details of your surgery.