The hip joint is one of the most important joints of the human body and represents the joint between the head of the femur (thigh bone) and the acetabulum (the hip socket). It is a ‘ball and socket’ type of joint which allows mobility and stability. The surface of the ball and the socket are covered by specialised lining; the hyaline cartilage or articular cartilage. Arthritis develops when the articular cartilage (lining) gets damaged due to various causes. Osteoarthritis or wear and tear is a condition where there is progressive thinning and loss of this joint lining. In extreme cases the lining is completely lost with a bone on bone joint which can be very symptomatic and disabling. Hip joint arthritis can also occur secondary to inflammatory conditions such as rheumatoid arthritis, ankylosing spondylitis, gout etc. This joint has a precarious a blood supply and not uncommonly the ball of the ball and socket joint loses its blood supply causing a condition known as avascular necrosis. Avascular necrosis can lead to secondary osteoarthritis. Hip joint arthritis can also be caused as sequelae to childhood hip disorder such as Perthes disease, trauma SUFE and aspherical articulation and subsequent impingement. Fractures around the hip can also lead to secondary osteoarthritis of the joint.
SYMPTOMS AND SIGNS:
Patients with hip arthritis would suffer from pain typically in the groin, thigh and buttock area. Occasionally hip arthritis can present as knee pain. Patients with hip arthritis would struggle to walk a reasonable distance and find it difficult to negotiate stairs. In worsening cases, patients may lose their ability to ambulate independently and may become reliant on a walking stick and crutches. They would find it difficult to bend down and tie their shoe laces and clip their toe nails on the affected side and would walk with a pronounced limp in the later stages. Hip arthritis could have a significant impact on a patients ability to carry out routine day to day activities.
ASSESSMENT:
A detailed assessment and history is initially obtained to find the cause of hip arthritis. On clinical examination the gait, any leg length discrepancy and range of motion of the hip joint is assessed. A diagnosis is most commonly confirmed by a routine plain x-ray of the affected hip. Occasionally in borderline cases or in cases where there is discrepancy between clinical symptoms and x-ray appearance an anaesthetic arthrogram (injection of the joint with local anaesthetic under radiological control) is carried out to confirm diagnosis.
THE OPERATION:
Typically the patient presents to the hospital on the morning of the scheduled operation and receives a regional anaesthesia. The anaesthetist will discuss and decide the most appropriate type of anaesthesia. The vast majority of patients have this operation under a spinal anaesthesia. Mr Mohanty routinely uses ERAS (enhanced recovery) protocol for all patients receiving hip replacement. This procedure involves injection of a cocktail of various medications including local anaesthetic during the operation and enables the patient to mobilise earlier as typically they do not require strong painkillers which makes them nauseous and drowsy in the post-operative period.
Patient’s after a hip replacement are encouraged to mobilise as soon as it is physically possible and would start to stand and walk the morning after, if not on the day itself. The length of stay in the hospital varies based on the individual and social factors but most patients with hip replacement are expected to leave hospital within three to five days after the operation.
PHYSIOTHERAPY AND REHABILITATION:
A programme of physiotherapy will commence soon after the hip replacement and will continue until the patient is independently mobile and has regained their independence and mobility. Some restriction in the range of motion and activities are limited for between six and twelve weeks from the operation. Although high impact activities are restricted after a hip replacement, with a modern hip component, patients often return back to activities such as skiing etc.
COMPLICATIONS OF HIP REPLACEMENT:
- Adopted from the British Orthopaedic Association Web Site
- Common complications (2-5%)
Deep vein thrombosis (blood clot):
Deep vein thrombosis presents with a painful swollen leg. The risk of vein thrombosis is greater after any surgery to the lower limb and pelvis. Deep vein thrombosis can lead to a serious complication called pulmonary embolism which may affect breathing. Patients are asked to be as mobile as they can after the operation. They are also asked to wear anti thrombo embolic stockings and foot pumps in the post operative period. Currently prophylaxis for deep vein thrombosis is carried out by administering oral medication which is to be taken for 35 days as per the NICE guidelines.
Bleeding:
Total hip replacement is associated with some intra and perioperative blood loss. Although most patients do not require blood transfusion and replacement after hip replacement in the current time, occasionally some patients may require blood transfusion in order to aid them to recover quicker after this operation.
Joint Dislocation:
Occasionally the artificial ball might dislocate out of the socket and may require anaesthetic to relocate the hip joint.
Leg Length Discrepancy:
The operated limb may rarely appear lengthened or shortened after the hip replacement. Most patients are able to cope with the minimal amount of leg length difference but may occasionally require a shoe insert.
Infection:
Infection, uncommon in modern day joint replacement surgery, still remains the most serious complication after a hip replacement. Antibiotics are administered around the operation but still 1-2% of patients with total hip replacement may have wound complication and infection. This may require washout or exchange of the hip replacement if the infection is not controlled.
Nerve Damage:
Very occasionally there could be damage to the sciatic nerve which runs very close to the hip joint and patients may present with either temporary or permanent damage with a foot drop or altered sensation of the leg after a hip replacement.