HIP JOINT: Basic Anatomy


  • Hip joint is formed by head of the femur (Thigh Bone) and cup like acetabulum of the pelvis. The upper end of the thigh bone is shaped like ball which snugly fits into the socket (Acetabulum) of pelvis bone.
  • The ball and cup of the hip joint is lined with smooth firm material cartilage, which cushions and allows smooth movement.
  • The joint is also lined with synovial membrane which produces joint fluid.
  • The ball of the thigh bone has a precarious blood supply, so any trivial trauma or insult can cause avascular necrosis of the femoral head.

Causes of hip pain: Damaged or Arthritic Hip

When the cartilage lining of normal joint wears or gets worn out it may result in pain and stiffness in the hip.

The cartilage may be damaged by

  • Ageing: a result of natural wear and tear which is termed as Osteoarthritis of hip.
  • Avascular necrosis of femoral head.
  • Injury / fractures around hip joint.
  • Diseases like Rheumatoid arthritis, Ankylosing spondylitis, etc.
  • In some individuals genetic factors may also predispose to early damage to cartilage.


Osteoarthritisis the most common type of arthritis. Primary osteoarthritis is commonly seen in elderly, above the age of 50 years. Osteoarthritis is a chronic condition characterized by wear and tear of the cartilage. As cartilage wears off the ends of bone rub against each other causing pain and stiffness. A young individual can develop secondary osteoarthritis due to trauma or diseases like Rheumatoid arthritis, Ankylosing spondylitis etc.


Avascular necrosis is a condition in which there is loss of blood supply to the bone due to fracture or vascular damage.  Avascular necrosis of femoral head can occur following trauma, using certain medicines and some medical diseases. As a result bone cells in the head of femur dies,then collapses, the joint is destroyed and patient develops painful and stiff joint. This can take 2-8 years to develop, but can happen at an early age too.

The most common causes of Avascular necrosis of femoral head are:

Trauma:Fractures and dislocations

Non Traumatic causes:

  • Alcohol abuse,
  • Use of steroids
  • Certain blood disorders


When medication,physical therapy and other conservative methods of treatment fails to relieve pain, total hip replacement may be recommended by surgeon.

How will Hip replacement help you?

  1. Improvementof quality of life
  2. Significant pain relief
  3. Mobility is increased.
  4. Help to lead independent and comfortable life
  5. Most of the replaced hip joints last for 10 to 15 years and patient can have pain free life

Getting ready for Hip replacement surgery:

  1. Medical evaluation: 
  2. Cardiac evaluation:
  3. Tests: Lab tests include Blood, urine and cardiac tests.
  4. Preparing your Hip: Surgeon examines your Hip prior to the surgery. There should be no skin infection, wounds around the Hip and skin should be clean.
  5. Others:
  6. Anaesthetic evaluation:  after getting all the blood tests and cardiologist opinion you will be examined by anaesthetist. He will evaluate you and gives you fitness for giving anaesthesia and advises different modalities of pain relief during postoperative period.


On the day before surgery:

  • You will be admitted in the hospital or asked to come directly to the hospital on the planned day of surgery.
  • You need to take the medications as advised by the anaesthetist.
  • You should have light dinner without much oil and spices and plenty of water. You should start fasting from 11PM on the day before surgery till further advice.
  • You should give consent and sign an informed consent.
  • Follow you anaesthetist and surgeons orders if any given to you in writing.
  • Have a neat shower.

On the day of surgery:

  • You should be on fasting, take your regular blood pressure and thyroid medications if any with sips of water at around 6 AM.
  • You can have a plain shower bath
  • Limb to be operated will be marked by the surgeon.
  • You will be shifted to operation theater half hour prior to surgery.
  • Anaesthetist will evaluate once again and prepares you for giving you anaesthesia.


Most of the Hip replacement surgeries are carried under Epidural and General anaesthesia. In rare cases when a patient is not fit for general anaesthesia, Hip replacement is performed under Spinal anaesthesia.

Postoperative pain relief is achieved by continuous Lumbar epidural pump.

Total hip replacement surgery:

Total Hip replacement is a surgical procedure in which damaged bone and cartilage is removed and replaced with prosthetic components.

There are 2 main components used in total hip replacement:

  • The acetabular shell replaces the hip socket
  • The femoral stem and head replaces the worn out top of femur

There are two types of Hip replacement

  • Cemented Hip replacement
  • Uncemented Hip replacement

Cemented hip replacement:

The damaged femoral head is removed and thigh bone medullary canal is prepared to take the femoral stem component. Bone cement is used to fix the femoral stem. A metallic ball is inserted on the top of the stem.

The damaged lining of cup (acetabulum) is removed by using special reamers. A plastic cup mimicking the original anatomy is fixed using bone cement.

The artificial joint is relocated and supporting tissues around the hip are sutured back.

Uncemented Hip replacement:

The damaged femoral head is removed and thigh bone medullary canal is prepared to take femoral component. The femoral stem is made to press fit into the bone

The artificial head is available in two materials – Metallic head

                                                                                   Ceramic head

The damaged lining of cup (acetabulum) is removed by using special reamers. A metallic cup mimicking the original anatomy is fixed using press fit and sometimes augmented with screws. There are three types of liners which can be inserted into the metallic cup:

Plastic liner

Ceramic liner

Metallic liner

After inserting appropriate liner the artificial joint is relocated and supporting tissues around the hip are sutured back.

There are various combinations of head and liners to make upnew joint

Metal on metal

Metal on poly

Metal on ceramic

Ceramic on ceramic


First 24 hours:

  • Immediately after Hip surgery you would be shifted to ICU (intensive care unit) and observed for at least for 24 hours.
  • After a day you will be shifted to ward of your choice.

First postoperative day:

  • On the bed you are advised to perform deep breathing exercises.
  • Ankle pump and static quadriceps exercises on the bed.
  • Gentle mobilization on bed with legs hanging down the bed and knee movement exercises.
  • If you are strong enough you would be made to stand.
  • Cemented hip replacement: walking with full weight on operated leg with walker.
  • Uncemented Hip Replacement: Walking without weight on operated leg with walker.
  • You will be shifted to ward. 

Second Postoperative day:

  • To continue the exercises on bed and walking with help of walker.
  • Drain tubes urinary catheter will be removed on the second day.
  • You need to take plenty of fluids and regular diet.

Third Postoperative day :

  • Depending on speed of your recovery discharge would be planned.
  • The dressing on the hip is changed to simple dressing.
  • You are advised to continue exercises and walking, gradually increasing the pace.

Fourth post operative day:

  • Some patients with slow recovery are discharged on 4th postoperative day.

Before you are discharged from the hospital, you will be helped to achieve:

  • Getting in and out of the bed independently.
  • Walking with the help of walker.
  • Using toilet or commode chair



 You should continue to stay active when you are at home for full recovery. However remember not to overdo it. You will observe gradual improvement and increased endurance over the next 6 to 12 months.

Tips to make you return home comfortable:

Planning your work:

You will be able to walk on crutches or a walker soon after surgery. But you will need help for many weeks with tasks like cooking, shopping, bathing and doing laundry. Make advance arrangements to have someone assist at home.

Home planning:

Before going for surgery, follow the steps given below to make your recovery at home easier.

  • Fix safety bars in your shower or bathroom.
  • Secure your stairways for support and safety.
  • Keep a stable chair, for your early recovery period, with firm cushion, firm back, two arm, and foot stool for leg elevation.
  • If you have low toilet seat, fix a seat raiser with arms.
  • Walking up or down the stairs within you pain limits and depending on your recovery.



  • Keep the wound area clean.
  • If your wound appears red or begins to drain, inform your doctor.
  • Check temperature regularly and inform your doctor if it exceeds above normal
  • Inform your doctor immediately if you have calf pain, chest pain, or shortness of breath.
  • Practice / initiate regular walking using crutches or walker.
  • Perform exercises to strengthen calf and thigh muscles.
  • Keep pillow between the legs if you want to turn to one side.


  • Do not bend.
  • Do not cross your legs.
  • Do not squat or sit on the ground.
  • Do not play high impact sports.
  • Do not jog, run or jump.
  • Avoid gaining weight as it can hasten wear and tear of the implant.
  • Do not shower or bath until the sutures are removed.


Physical therapy exercise :

Continue to exercise as instructed by your physiotherapist or doctor for at least 2 months after surgery.

  1. Frequent deep breathing exercises.
  2. Ankle Pumps: Move your ankle up and down to squeeze the calf muscles.
  3. Static quadriceps:  Sit with your legs straight and keep a rolled towel under your knee. Press the knee against the towel while tightening the thigh muscles. Hold this for a count of 5 to 10.
  4. Knee straightening exercises: place a small rolled towel just above your heel.Tighten your thigh. Try to fully straighten your knee such that the back of your knee touches the bed. Hold for 5 to 10 seconds.
  5. Knee bending: Sit on your bed side or chair with your thigh supported. Gradually allow your leg to fall down gently on its own weight. Now gently try to push your leg backwards till the back of the leg touches the chair or cot edge. Hold your knee in this position for 5 to 10 second. Gradually try to lift the leg upwards initially with support of other leg or physiotherapist. When the leg becomes straight maintain it for 5 to 10 seconds.
  6.  Weight bearing