| | | | | prosthesis. Moreover wear debris from the |
| | | | poly-etheylene liner lead to osteolysis and bone loss. |
| | | | | When this first hip is to be changed or revised after |
| Dr.A.K.Venkatachalam, | | | | its lifespan more bone loss occurs. Conventional hips |
| | | | | have a small ball to reduce friction and wear, but the |
| Consultant orthopaedic surgeon | | | | ill effect of this is an increased risk of dislocation. An |
| | | | | average dislocation rate of 3- 4 % has been |
| | | | reported. These implants do not last very longer than |
| | | | | 20 years and revision rates of 50% at 20 years have |
| Hip arthritis in India affects young and middle aged | | | | been reported. Survival rates are less satisfactory for |
| persons unlike the west where Primary hip | | | | the relatively younger active patients. Thus a total hip |
| osteoarthritis pre dominantly affects the elderly. | | | | replacement is not an ideal implant for younger |
| Surgery in this group of relatively younger patients | | | | patients less than fifty years old who need a new |
| requires newer techniques and implants. This article | | | | hip. |
| will shed light on the disease and the current | | | | |
| modalities of treatment available. | | | | Problems with conventional total hip replacement: |
| Types of Hip arthritis | | | | |
| | | | | - Excessive bone sacrifice and loss |
| Hip arthritis is classified as Primary and secondary | | | | - Increased risk of dislocation |
| Osteoarthritis. | | | | - Patients cannot squat or sit cross legged on the |
| | | | | floor with out the risk of dislocation. |
| Primary osteoarthritis is age related wear and tear | | | | - Range of movement is less |
| arthritis. It is rare in India. | | | | - Patients cannot involve in sports |
| | | | | - Poor survival in young and active patients they |
| Secondary osteoarthritis occurs at a younger age | | | | require earlier revision. |
| and is more common. Rheumatoid arthritis, avascular | | | | - Revision surgery is difficult |
| necrosis, traumatic arthritis and other connective | | | | - The hip feels less like a normal hip |
| tissue disorders like SLE, Psoriasis etc. all lead to | | | | - The cup wears with time and plastic from it harms |
| secondary osteoarthritis. | | | | bone |
| Rheumatoid arthritis is an auto immune disorder, | | | | - Change in length of the leg after surgery leading to |
| affects all joints particularly the small joints but also | | | | leg length discrepancy. |
| does not spare the hip and knees. | | | | Why remove normal bone when only the surface of |
| | | | | the ball is bad? |
| Avascular necrosis is a condition that reduces the | | | | |
| blood supply to the end of the bone. It affects | | | | This is the logic behind hip resurfacings. This bone |
| patients with excess alcohol intake, consuming | | | | preserving hip resurfacing involves replacing only the |
| steroids, connective tissue disorders like SLE. | | | | diseased bony surfaces of the head of femur and |
| Systemic lupus erythematosus (SLE) is a connective | | | | acetabulum. This involves sculpting the head of the |
| tissue disorder affecting mainly young women A | | | | femur and covering it with a metal cap and fixing an |
| photo sensitive rash on the cheeks, renal involvement | | | | uncemented socket into the acetabulum to receive |
| and arthritis are some notable features. Avascular | | | | the head. |
| necrosis affects a proportion of the patients with | | | | Hip Resurfacing- A bone preserving hip replacement! |
| SLE. | | | | |
| | | | | Preservation of bone and less stress shielding makes |
| Gaucher’s disease is a genetic storage disorder. | | | | it easy to revise this hip if needed. The large head |
| | | | | size provides a very stable joint and recreates the |
| Post traumatic arthritis occurs after a severe injury | | | | sensation of a normal hip joint. Patients have gone |
| to the hip. Fractures of the ball (top of the femur) or | | | | back to playing Judo and Squash after this operation. |
| socket (acetabulum) can lead to arthritis after | | | | Advances metallurgy makes the metal on metal |
| inadequate treatment. | | | | articulation likely to survive longer in the young and |
| Hip arthritis is very disabling as it is a small ball and | | | | active patient. With less metal inside the bone and |
| socket joint unlike the Knee joint which is a large one. | | | | less invasion of the medullary cavity of the femur, |
| In advanced disease a total hip replacement was | | | | the risk of infection is reduced. Rehabilitation is faster |
| recommended by Orthopaedic surgeons until recently. | | | | and better. |
| Advances in orthopaedic surgery now cater to the | | | | |
| specific requirements of these younger patients. | | | | Advantages of hip resurfacing: |
| Surgical solutions | | | | |
| | | | | - Allows the patient to squat and sit cross legged on |
| These are the mainstay of treatment as | | | | the floor safely |
| conservative measures fail to relieve pain. Total Hip | | | | - Allows a normal range of movement |
| replacement (THR) is a time tested operation and | | | | - Sacrifices only the surface diseased bone and |
| has a success rate of 93 % survivorship at 10 years. | | | | preserves normal bone |
| | | | | - Imparts a more normal sensation |
| The hip joint may need to be replaced with an | | | | - The joint is likely to last longer even in younger and |
| artificial joint when it is irreversibly damaged and | | | | active patients. |
| cannot be salvaged by alternate surgery. The patient | | | | - Earlier and faster rehabilitation |
| complains of pain and restriction of movement. The | | | | - Less risk of dislocation |
| pain may often be referred to the knee or felt in the | | | | - Easier to revise if needed. |
| knee and no hip symptoms. Occasionally the pain | | | | - No leg length discrepancy |
| may be felt more in the buttock area rather than in | | | | Proxima hip replacement – A perfect bone |
| front of the groin. | | | | preserving hip replacement? |
| Who needs a hip replacement? | | | | |
| | | | | This is the latest addition to the armamentarium of |
| In India, many young patients with ankylosing | | | | the hip surgeon in India. It is a bone preserving hip |
| spondylitis, avascular necrosis, post septic arthritis, | | | | replacement. |
| post injury suffer from hip arthritis and are advised a | | | | |
| hip replacement for disabling pain. Thus many hip | | | | In this operation, the entire diseased head of the |
| replacement operations are performed in younger | | | | femur is removed. The lining of the hip socket is |
| patients. The surgery should cater to the enhanced | | | | resurfaced with a metal cup. A tiny uncemented hip |
| demands on an artificial joint by younger and more | | | | with a short stem called the Proxima hip is impacted |
| active patients. Naturally an operation designed for | | | | into the upper end of the femur or thigh bone. |
| Western elderly patients is not suitable for younger | | | | The size of the implant matches the natural one and |
| patients. | | | | hence the risk of dislocation is almost eliminated. It is |
| What is a total hip replacement? | | | | recommended when the bony destruction is |
| Fig1. Shows the differences between a normal THR | | | | advanced and hence unsuitable for resurfacing and a |
| on the left and a Proxima hip on the right | | | | total hip replacement would be overkill. The |
| In this operation the ball shaped upper end of the | | | | advantages of the Proxima are |
| thigh bone (femur) and the socket (acetabulum) are | | | | |
| replaced. The ball is replaced with a long metal stem | | | | - suited for minimally invasive surgery |
| that is fixed into the upper end if the thigh bone. Its | | | | - No thigh pain |
| upper spherical end articulates with a cup shaped | | | | - Metal on metal – confers longevity |
| polyethylene socket that is cemented into the pelvis. | | | | - Conformity to normal size eliminates risk of |
| | | | | dislocation |
| Conventional hip replacements sacrifice a great deal | | | | - Ability to correct biomechanical abnormalities makes |
| of normal bone as the head, neck, and upper part of | | | | this superior to resurfacing. |
| the thigh bone is removed for implantation of the | | | | |