Total Hip Replacements
Last year, I did a blog post about total knee replacements. I fiugred that I better do about total hip replacements. This operation is another very common one that happens in Canada. There were 24,253 in Canada in 2006-2007 and the number keep rising annually. There were 310,800 total hip arthroplasties, THA’s, done in the USA in 2010. The hip joint is where the top of the femur, the femoral head, attaches to the acetabulum, socket in the pelvis. The femur is the longest and strongest bone in the body. The top part of the bone is part of the hip joint, the bottom part of the bone is part of the knee joint. The hip joint is a ball and socket joint. There is a lot of mobility in the hip joint. In the buttock and the groin area are where the muscles that support the hip joint are located. In the buttock, the muscles that typically support the hip are the glutes, gluteus medius, gluteus minimus and a multitude of small hip external rotators, like quadratus femoris, they turn the leg outwards. In the groin area, the main muscle that supports the hip joint is pectineus. Pectineus almost aligns perfectly with one part of the glute med muscle. Together they are thought to be orientated along the neck of the femur, to pull the head of the femur into the acetabular socket. The acetabular socket is lined with cartilage as well, the femoral head is covered with cartilage. There is a joint capsule around the hip joint. The joint capsule keeps the synovial fluid in the joint, which helps to lubricate and give nutrition to the cartilage.
When is someone ready for a THA? One criteria, is when your doctor does an xray of the hip joint and they do not like what they see. What is normal? The femoral head with a good pocket of space around it then the acetabulum. The radiologists will usually compare the xray of the painful side to the non painful side. If the space around the femoral head is minimal, most common is the superior aspect of the acetabulum and femoral head, then there is degeneration of the cartilage in the joint. Another aspect possibly getting a hip replacement, is where the client is having their pain. I see many people that complain of ‘hip’ pain and the pain is their buttock. That is not the area for hip joint pain to occur. Pain in the buttock area can be caused by the low back, sciatic nerve or the muscles of the buttock, i.e. the glutes. Pain that arises from the hip joint itself is most likely to be found in the groin area, almost along the groin crease. These are a couple of the things that surgeons look for when deciding if the client is in need of a hip replacement.
What happens in a total hip replacement surgery? Honestly, I am not completely sure. I have never seen a THA surgery. I have seen multiple total knee replacement surgeries but not one in the past 10 years. There are a number of different techniques when doing the hip surgery. There is an anterior, lateral and posterior approaches. With an anterior approach, the incision is done on the anterior part of the hip area. The main complication in this technique is the possible cutting of the femoral nerve. The femoral nerve supplies the sensation and motor function to the groin and anterior thigh muscles. I have rarely seen this approach, as the risk of that complication is simply too high. The lateral approach is much more common, in fact, I think the vast majority of the clients I see have had the lateral approach. The surgeon comes in and cuts the gluteus medius muscle and separates it to get access to the hip joint. There is also the posterior approach to the hip. This is when the incision is made on the posterior aspect of the hip, the client may be lying on their front during the operation. The main complication of the posterior approach is the increased possibility of hip dislocation. To combat this, there is more of a restriction of hip flexion, post op than normal. I have seen a few clients that have had this approach, one of the orthopaedic surgeons from Penticton, I believe does this approach. I believe his clients are restricted to no greater than 70 degrees of hip flexion. Below is a video of a total hip arthroplasty (this a video of a real person getting their hip replaced, if you are squeamish, you may not want to watch this video). This brings me to my next topic, restrictions post THA. There are typically three restrictions. First, no hip flexion past 90°. The reasoning for this is that the majority of hip dislocations occur posteriorly, or out the back of the hip joint. The more the hip is flexed, think of knee to chest, the better the chance that the hip could ‘pop’ out the back of the joint. Typically this is for 3-6 months, although some surgeons put restrictions on for life. The second restriction post THA is no pivoting on the surgical leg. The reasoning is similar to above, to decrease the chance of dislocation. The muscles of the hip joint are very weak post surgery and it takes, 6 – 10 weeks to get them stronger again. In reality, it takes someone very dedicated to strengthen the hip/glute/groin muscles the weeks following the surgery. The third, and final restriction post THA surgery is no crossing the midline with the surgical leg, meaning no crossing the legs. This thought to be because it places stress on the lateral incision of the hip and makes it possible to dislocate the hip. There was a review article done in 2015, I believe that reviewed these restriction and what they found was the number one chance of dislocation was a poor surgery performed by the surgeon. An interesting note, is that in Kelowna, the orthopaedic surgeons have gone from 3 restrictions to 2 restrictions, post op. They decided to allow clients to cross the midline with their leg, post op. That got me thinking that typically we get the clients out on their surgical leg side, as it does not cause the leg to cross the midline. The downside of getting clients out on their surgical side is that they pivot on the surgical hip when getting out of bed. Now with that restriction gone, I have started getting clients out of bed on their non-surgical side. This way, they pivot on the non-surgical hip side, much less painful. In addition, the Kelowna orthopaedic surgeons only keep the restrictions on for 6 weeks. Pretty cool. Clients that get a THA do not complain of pain in the same way as clients that get a total knee replacement. Clients with a TKA complain of pretty severe pain, however, clients that have a THA still complain of pain, don’t get me wrong, but they complain almost more of stiffness. Many of the clients once they start doing the exercises find a lot of relief with them.
The operation itself takes about 90 minutes and the client typically stays in the recovery room, 2-3 hours. We see the clients up on the floor, 4W, three to four and half hours post operation. After the client comes up to the acute surgical floor, is when the physiotherapist gets involved. Typically the day of the surgery is counted as day zero, same as a total knee replacement. As long as the client can feel their surgical leg and can wiggle their toes we can work with them. If the client cannot feel their leg or wiggle their toes, I try to just pop in and say hi to them and go over the exercises and let them know what to expect. As well, I might get them up standing and possibly ambulate using a two wheeled walker. How many times has someone asked me to get them up and when they stand up they just about pass out? Way too many times, it is very common. For this reason, I am not eager to get people up standing day zero. There are typically four exercises we do with the client, post op day one. Day one is the first day after their surgery. For the first couple of days, the client does need some help with the exercises. For example, doing a heel slide while lying on their back, I help to lift the knee and guide the heel. This exercise seems to be one of the most helpful for eliminating the ‘stiffness’ in their new hip. Second exercises is supine, lying on their back, heel slide then lift their leg off the bed. Again, some help is needed with this exercise. Thirdly, supine abduction, moving the leg away from the midline of the body out to the side. And finally quads over a roll. After they do the final exercise, I help them get out of bed and we go for their first walk. Most of the time people with hip replacements are WBAT. WBAT = weight bearing as tolerated. I make sure to let the clients know that just because it hurts does not mean that they are doing any harm to the new hip. Many people are happy to hear that because they have associated pain with damage to the old hip. Day two, is when the rehabilitation assistant, RA, comes to see the client. The RA’s will do the exercises with the client, get them up walking and do the stairs with the client. Some clients do not want to do stairs because they live in a condo without any stairs or they live in a rancher style house. I tell them that we live in a world of stairs. Their house may not have stairs but just wait until you have to step up on the curb or to go to a restaurant… The vast majority of people with a total hip replacement go home on day two or three post op. Clients with a total knee replacement usually go home day two post op. If you have any questions about total hip replacements of THA’s, please leave a comment or contact New Leaf Physiotherapy. We would love to discuss your upcoming or recent THA with you.