The hip joint is one of the largest weight bearing joints in the human body. It plays a vital role in mobility and stability. A variety of causes may lead to destruction of this joint such as Osteoarthritis (most common). When this happens, replacement of the damaged portion is essential for alleviating pain and improving the quality of life.
Multiple factors may lead to hip joint damage, the common causes are listed below-
Osteoarthritis: it is caused due to the degradation of cartilage lining which allows smooth motion between the bones within the hip joint. As a result, the bones begin to rub against each other resulting in wear and tear, causing severe pain with movements of the joint.
Hip fracture: Fracture by itself or due to complications such as avascular necrosis or non union (the bone does not unite even after sufficient time as required for healing has passed) damages the joint requiring replacement surgery.
Rheumatoid arthritis: Misdirected action of immune system on the joint lining causes rheumatoid arthritis. It can lead to hip damage.
Hip dysplasia : It is the abnormal growth of hip bones. Hip replacement will be necessary to correct hip dysplasia. Mostly, younger individuals are affected with these kinds of disorders.
Avascular Necrosis : It is the deformity in the joint caused by reduced blood supply of the head of femur bone leading to its collapse. It is common in smokers, deep sea divers and with prolonged steroid use. Young individuals are commonly affected.
Symptoms & Indications
The common symptoms that patients face are:
- Continuous pain affecting day-to-day activities.
- Difficulty in walking
- Shortening of the leg
- Inability to squat
- Reduced hip movements
The realistic results that the patient can hope to achieve following a hip replacement surgery are
- Significant pain relief
- Improved ambulatory status
- Increased hip movements
- Correction of shortening
- An active lifestyle not limited by pain
The limitations of the surgery are
- Patients cannot squat/ sit crosslegged on the floor or use Indian commodes
- Patient cannot be involved in high energy activities and contact sports
- Implants get worn out over a period of time requiring revision surgery
Types of joint replacement
They are broadly categorized into two types.
Partial hip replacement (Resurfacing) :As the name indicates, only a part of the hip which is worn out is replaced. Hip joint is made of 2 bones – the cup of the pelvic bone and the head of thigh bone (femur). When only the head is involved, then this surgery is the ideal choice.
Total hip replacement: Total joint arthroplasty is indicated when both the cup and the ball (femur head) get worn out. This is the most commonly done surgery and has good results in terms of pain and activity level.
Hip replacement may be cemented (where the artificial prosthesis are fixed to the bone with bone cement) or uncemented.
Patients with the above mentioned indications are ideal candidates for joint replacement. Age is not a major criterion for joint replacement but symptoms are. Patients with associated co-morbidities like diabetes, hypertension, heart conditions, lung and urinary tract infections, dental caries etc. need a complete pre operative evaluation before deciding on surgery.
A variety of implants are available in the market for joint replacement surgeries. They are available in stainless steel, cobalt chromium alloys, titanium alloys, tantalum alloys, zirconium alloys and the newer oxinium implants. Different prosthetic designs are available to increase the longevity of the prosthesis. They may be cemented or uncemented. Implant selection is primarily dependent on patient factors and expectations. The cost also plays an important role in our society.
The normal inpatient time in the hospital varies from 7 to 10days. The stages involved in preparing for the surgery are
- Pre operative
- Intra operative
- Post operative
- Home care
Pre operative work up:
Pre operative work up starts with a Consultation with the Orthopaedic Surgeon which lasts for about 45 minutes. It includes a detailed history, general physical examination, hip joint examination, x-rays, blood investigations, ECG, Echo and patient counseling. Patient will additionally have to meet a Physician, a Cardiologist, an Anaesthetist and sometimes a Gynecologist for pre operative assessment of their general condition. Blood transfusion may be required in the pre, intra or post operative period in patients with low blood levels. Pre operative work up can be done as an inpatient or outpatient. Once the patient is fit for surgery, he or she is admitted for undergoing the procedure.
Patient counseling: It involves a detailed discussion about the hospital stay and surgery, the realistic expectations that the surgery can achieve, the limitations of the surgery, the choice of prosthesis, the post operative rehabilitation protocol, social and home planning and finally the complications that may occur during or after the procedure.
Intra operative period:
After admission, the patient is kept on empty stomach for a minimum period of six hours prior to surgery. The hip joint is prepared an hour before surgery and the patient is shifted to the operation theater half hour before the scheduled time. The surgery lasts for a period of about 2 hours. The anesthesia routinely administered is spinal or epidural anesthesia where the patient is awake during the procedure but both the legs numb below waist level. The other type is the general anesthesia where the patient is put to sleep.
After giving anesthesia, an incision of suitable size is made on the hip. These incisions can be of different types such as posterior, lateral, anterior, and antero-lateral depending on the Surgeon’s choice. The original hip joint is removed and immediately replaced with an artificial one through this incision. Metal components may be fitted onto the bone using an appropriate cementing material. Adequate support will be provided by a polyethylene acetabular cup and a ceramic head placed within the metal component. The wound is closed with stitches. After the surgery patient is shifted to the post operative recovery room. Blood transfusion may be given as required during or after the surgery
Post operative period:
Day 1:The patient is usually made to sit and stand on the 1st post operative day. Diet is normalized. Antibiotics and thromboprophylaxis (agents which prevent clots from forming in leg veins following prolonged immobilization in bed) are continued. If they are comfortable, they are even made to walk a few steps. Pain is controlled by epidural catheters which are retained for 2 days.
Day 2:Wound is inspected and dressing is changed on 2nd day. Drain tube is removed. The patient is made to walk further more with support of a walker. They are given commode training and exercises. Recovery is generally quick and one can perform his/her daily activities but with some care. Injectable medications are converted to tablets.
Day 3 to Day 5:It involves aggressive physiotherapy and exercises. Stairs climbing is usually delayed. Patient is discharged once mobilization is satisfactory.
Home care involves wound care and home physiotherapy. The success of a replacement surgery depends a lot on home physiotherapy. Physiotherapists visit patients at home to assist them in rehabilitation till they are satisfied that they can continue training by themselves. They normally provide home physio for a week to 10 days. The dressing should not be disturbed and should be water free. Dressing is changed after 5 days and sutures are removed after 10 to 12 days.