Knee replacement surgery is generally very successful, and complications are relatively uncommon, considering the complexity of the procedure. However, complications can occur following a knee replacement, as with all major surgical procedures. They include excessive swelling or bleeding, blood clots (DVT or deep vein thrombosis), pulmonary embolism (PE), phlebitis, neurovascular damage, skin healing problems, subcutaneous stitch abscess, peri- and intra-articular infection, limited flexion or extension or both, stiff joint (arthrofibrosis), early loosening of implants, allergy to the metal parts of the implants, fracture of the knee bones, etc. There are also anaesthetic risks, both during and after the procedure.
Our duty is to educate patients regarding risks associated with higher levels of activity after total knee replacement: implant loosening, accelerated wear of the articulating surfaces and injuries. We advise our patients to avoid recreational and athletic activities until their quadriceps and hamstring muscles are sufficiently rehabilitated. After muscle strength has been recovered, we try to help our patients to make reasonable choices regarding athletic activities. In general, we support and encourage low-impact activities: cycling, golf, dancing, riding, walking (but not jogging), swimming and tennis (but not squash). Please see recommendations for more information:
For a hip replacement to function well, the ball must be retained within the socket at all times. Several factors must work in concert to keep this mechanical relationship intact, including proper alignment of the acetabular prosthesis (the socket) and the femoral prosthesis (articulating ball part). In addition, the muscles that attach to both the pelvis and the femur must be strong and able to withstand pressure. Sometimes the muscles of the elderly patient are quite weakened with age or health related issues and are unable to hold the ball in the socket.
: Knee replacement implant - PFC Sigma cruciate retaining non-porous size 5 left femoral component (part number 960005) manufactured by DePuy International Limited. Lot numbers of affected devices, which were manufactured from 20 January to 30 April 2009 inclusive are listed .
There is no universal agreement as to when it is safe to travel by plane after a knee replacement. It seems that most orthopaedic surgeons advise their patients not to fly for at least 4 to 6 weeks before and after a knee replacement. Although short flights do not seem to be a problem long intercontinental flights are a potential problem as there is an increased incidence of spontaneous DVT (deep venous thrombosis), even in the young and healthy passengers. It is possible that sitting for long period of time, in a confined space and with very little leg room, could predispose to the development of deep venous blood clots, especially in people following recent major knee surgery. The likelihood of developing postoperative leg blood clots depends on many different factors, including your general health, medical history, postoperative mobility and a number of risk factors (obesity, smoking, a history of DVT, etc.). If you have to travel by plane, before 4 weeks after your knee replacement, it would be wise to contact your airline’s Medical Department and to ask them for advice. Also, please discuss this issue with your GP, as you should take further prophylactic measures for several weeks.
Finally, revision hip replacement surgery has a less predictable longevity. Typically a revision hip surgery done for loosening or instability is secured to less healthy bone and as such will not bear up as well to the stresses of living as well as when the bone was of better quality when the patient was younger and more active. Additionally, if the revision was done for an infected hip replacement, the risk of a re-infection is high with studies that indicate that in 10 – 15% of the joints the infection is not cleared and they become infected again . Re-infected joint replacements are particularly difficult challenges for the patient and the surgeon.
Despite thorough preparation, the risks involved in revision hip replacement surgery are increased several fold from the level of risk of a primary hip replacement. The surgery is more difficult and time consuming, the soft tissues, nerves and blood vessels more difficult to mobilize and protect and the prostheses are more complex to implant properly into the supporting bone. The soft tissues become more difficult to stretch and the pain of revision hip replacement surgery can be an obstacle to full mobilization of the joint. Notably, it is important that patients realize that the revised hip frequently never reaches the same level of function as did the first hip replacement. Complications and chronic pain are far more common with revision hip replacement surgery than it is with primary hip replacement.
The prevailing principal in dealing with any fracture around the hip is to gain stability of the fracture and then gain stability of the hip replacement. Both the bone and the prosthesis must be stable to allow any weight bearing. It is rare that full weight bearing is allowed before the fracture is healed. In addition, if the prosthesis comes loose from the fractured bone the surgeon will typically try to bypass the fractured area of the bone to obtain firm fixation on bone further down the shaft. On very rare occasions it may be necessary to replace most of the shattered femur with a very large hip replacement prosthesis referred to as an oncologic prosthesis, one that is used in cases where a tumor has destroyed the bone.
Nevertheless, as a cause leading to revision hip replacement, infection is the third most common. In several studies which assess the causes of primary hip replacement failure, infection of the joint is the most challenging and potentially devastating cause with 15% of all revision hip replacement procedures being done for this reason . If an artificial joint becomes infected, the pain is typically more constant than with a loose, but non-infected joint, but symptoms greatly vary with the type of infecting organism. Along with pain, symptoms include a stiffening of the joint, making movement quite difficult. On rare occasion, a prosthetic joint infection can make the patient systemically ill with fever, chills, weight loss, and lethargy.
Once the hip is exposed, the very important step of removing the old hip replacement is begun. When the reason for the revision hip replacement surgery is mechanical loosening, otherwise known as aseptic loosening, with extensive osteolysis of the bone, one or all components are not well-fixed to the supporting bone and can be removed with relative ease. Unfortunately, when this is the case, there will be large cavitary bone defects that will need to be reconstructed in some manner to fill in these holes in the bone with either bone cement or bone graft.
The most common situations that lead to the need for a revision hip replacement are instability / dislocation, mechanical loosening and infection. According to one national review study, instability issues account for 22% of all revision hip replacements, aseptic loosening for 20% and infection the cause of 15% of yearly revision hip replacement surgeries . Periprosthetic fracture, component failure and osteolysis-related wear are the causes for the remaining revision hip replacements done each year. Of great concern looking forward is that infection by the year 2030 will account for 48% of all revision hip replacements that will be done . This has grave economic implications as infection is one of the most expensive complicating events related to joint replacement surgery.