|Total Hip Replacement|
|Which type of hip prosthesis?|
|Types of hip prostheses|
|Fixation Of The Prosthesis|
|prevention of thromboses|
As with any type of surgical procedure, there are certain risks or complications associated with total hip replacement. We aim continually to provide the optimum environment for your surgery and recovery, minimizing any potential complications. You always are free to ask for more information if required.
In case of revision surgery, specific complications related to the individual surgery will be discussed with the patient before surgery. Our primary goal is to assist you through your total joint replacement procedure with minimal complications and maximum recovery. Therefore, we will be instructing you in guidelines that will aid in the healing process.
The most encountered complications are :
- Deep Vein Thrombosis (DVT) and Pulmonary Embolus (PE)
Post-operative DVT is one of the most common complications following hip and knee surgery, and is caused by immobilization in combination with damage of the veins because of the manipulation during operation. Pulmonary embolism (blood clot traveling to the lung) can be fatal and can occur suddenly. Several measures are used to prevent the formation of blood clots in the legs : TED stockings day and night during hospital stay, bed exercises and blood thinning drugs (Low Molecular Weight Heparin) subcutaneous once a day during 3 weeks (see Guidelines for Returning Home). See further exercise section below.
Dislocation occurs when the ball of the hip joint pops out of the socket. It is uncommon and usually preventable after hip replacement surgery. Prevention depends largely on patient education and care in the postoperative period (see Guidelines for Returning Home).
Hip dislocation can occur at any time after surgery. However, it is most likely to occur within the first six weeks post-operatively. The muscles and soft tissue (capsula) around the hip socket are healing during this time. They are not strong enough to hold the ball in the socket when the hip joint is under certain kinds of stress. Movements and positions that produce these stresses should be avoided in the post-operative period. Hip dislocation is usually accompanied by a pop or noise, and by pain in the groin and/or buttocks. The affected leg will feel and look either much shorter or occasionally much longer. The foot may be rotated either outward or inward. Patients are mostly unable to bear weight or walk on the affected hip. A hip dislocation is not life threatening but should be treated promptly. Dislocation is confirmed by X-ray. If the hip is dislocated, it is usually reduced (put back in position) under general anesthetic. This procedure is called a closed reduction; a surgical incision is not required. Very rarely, the hip cannot be relocated by closed reduction and an open reduction (through an incision) is required. Dislocation rate of 1% is reported as usual following total hip replacement, reaching 10%-15% after revision surgery. When performing a resurfacing procedure, the chance for dislocation is extremely low. In our series of 1900 procedures so far, we have seen only 6 dislocations! The reason for that is the use of much larger diameters (36-58 mm) of the head, in stead of the small heads (22-32) more often used in classical THA (see article). This creates a larger intrinsic stability. For that reason we started using the same principle in revision surgery, using larger diameters of the head in the articulation with metal-on-metal, using a dysplasia cup or a resurfacing cup component. The large modular metal head suits perfectly on the stem in the femur (Eurocone). In this way we hope to reduce the chance for dislocation after revision surgery to an absolute minimum (4% in stead of 14%).
- Nerve injury
Any incision can result in damage to the sensory nerves in the area of the incision. Significant nerve damage, which may cause loss of muscle function, can occur after hip replacement. This type of injury is rare and is most common when the leg is lengthened more than one inch (such as in surgery for congenital hip deformity or revision total hip replacement). Nerve injuries of this type can lead to a ‘foot drop’ or the inability to raise the ankle or toe, in case of damage to the Ischial Nerve.
In case of palsy of the Femoral Nerve, there will be inability to keep the leg extended during gait. Most palsies recover spontaneously.
In case of an sciatic nerve problem, recovery is less common. It can take 2 years to be able to see any recovery.
In case of drop foot electrostimulation is done in the beginning. Bracing and special tools can help. The recovery of a sciatic nerve palsy is less obvious then a femoral nerve palsy.
- Fracture of the shaft (femur)
When inserting the femoral stem (prosthesis), it might happen that the shaft of the femur fractures due to severe osteoporosis or bone loss in case of revision surgery due to osteolysis. Several types of adapted prostheses and materials are available to cope with this problem.
Overall incidence of infection is approximate 1%. Infection may occur early, within 6 weeks or late, even years after surgery. Early infection is treated with antibiotics and possible re-operation to clean out the hip and try to save the prosthesis from removal. Late infection generally requires re-operation with removal of the prosthesis and possibly a second stage operation to re-implant a new hip when it is safe (after 6 weeks of intravenous antibiotics). A 2-stage revision can be done with use of an antibiotic impregnated spacer. In my institution a 1-stage procedure is performed unless this is not possible anymore for some reason. See also Revision Surgery.
- Blood loss and transfusion
Joint replacement surgery involves significant blood loss usually requiring blood transfusion. Banked ‘homologous’ blood from Red Cross donors is stringently screened and tested to ensure that it is safe and free from infectious agents such as HIV and Hepatitis. Nevertheless, there is no guarantee that blood from ‘homologous’ donors is safe, or will not cause a blood reaction. The risk is extremely low.
In primary hip procedures and resurfacing the risk of bloodtransfusion is becoming low (see results page). In bilateral hipprosthesis a bloodtransfusion is more often used (see results page). In these cases a cellsaver is used.
- Leg length discrepancy
Most total hip replacements are unconstrained. This means that the ball is not locked into the socket, and the hip can theoretically dislocate with extreme movement. Stability is produced, in part , by soft tissue tension in the muscles and ligaments around the hip. Sometimes it is necessary to lengthen the leg, which tightens the soft tissues, to improve the stability of the hip. Leg length difference is usually less than 5 mm in the vast majority of cases, but can be up to 2.5 cm in unusual circumstances, requiring a shoe raise the other side. Some patients feel longer after hip replacement without true lengthening. This is called “functional leg length discrepancy” and is due to tightening of the muscles around the new hip. This feeling of lengthening of the leg can take 6 weeks to 3 months to improve and requires stretching exercises of the hip and pelvis.
In our service leg lengthening is in all cases NOT RECOMMENDED.
- Heterotopic ossification - HO
This is an abnormal calcification/ossification of the muscles around the hip joint, creating a stiff hip joint! Prevention consists of daily admission of indomethacin (or another NSAID), a strong anti-inflammatory drug, during 3 weeks after surgery. In case of contraindications for admission of the drug (e.g. Stomach ulcer) or when patient is severe at risk for HO (e.g. spondylitis ankylosans – Bechterew disease), a single dose of radiation (700 rad) is given the day before or after the operation to prevent HO. When the hip becomes completely stiff, surgical resection of the ossification is mandatory (see also publication: Early Resection of Heterotopic Ossification after THA).
[reference : http://www.jru.orthop.gu.se/ - annual report 2003 p. 23]