Hip treatments & procedures
When the head of the thighbone slips out of the socket in the hip bone. In most cases, the thighbone is pushed out of its socket in a backwards direction (posterior dislocation). This leaves the hip in a fixed position, bent and twisted in toward the middle of the body. The thighbone can also slip out of its socket in a forward direction (anterior dislocation). If this occurs, the hip will be bent only slightly, and the leg will twist out and away from the middle of the body.
A hip dislocation is very painful. Patients are unable to move the leg and, if there is nerve damage, may not have any feeling in the foot or ankle area. Motor vehicle accidents are the most common cause of hip dislocations and wearing a seatbelt can greatly reduce the risk. Falls from a height or industrial accidents can also generate the required force to dislocate a hip.
Often other injuries will be present, fractures to the pelvis and legs, back injuries even head trauma. A hip dislocation is an orthopaedic emergency. Call for help immediately. Do not try to move the injured person, but keep him or her warm with blankets.
Hip dislocation can be diagnosed simply by looking at the position of the leg. X-rays will reveal any additional fractures in the hip or thighbone. If the patient has no other complications, the physician will administer an anaesthetic or a sedative and reposition the displaced bones. Surgery may be required to do this.
A hip dislocation can have long-term consequences, particularly if there are associated fractures. As the thighbone is pushed out of its socket, it can disrupt blood vessels and nerves. When blood supply to the bone is lost, the bone may die. The protective cartilage covering the bone may also be damaged, which increases the risk of developing arthritis.
The extent of the break depends on the forces that are involved. The type of surgery used to treat a hip fracture is based on the bones and soft tissues affected or on the severity of the fracture.
Hip fractures most commonly occur from a fall or from a direct blow. Some medical conditions such as osteoporosis, cancer, or stress injuries can weaken the bone and make the hip more susceptible to breaking. In severe cases, it is possible for the hip to break with the patient merely standing on the leg and twisting.
Patients with a hip fracture will experience profound pain over the outer upper thigh or in the groin. There will be significant discomfort with any attempt to flex or rotate the hip.
If the bone has been weakened by disease, the patient may notice aching in the groin or thigh area for a period of time before the break.
If the bone is completely broken, the leg may appear to be shorter than the non-injured leg. The patient will often hold the injured leg in a still position with the foot and knee turned outward.
Diagnosis is generally made by x-ray. In some cases an MRI scan will reveal a hidden fracture. In general, there are four different types of hip fractures.
These fractures occur at the level of the neck and the head of the femur, and are generally within the capsule. The capsule is the soft-tissue envelope that contains the lubricating and nourishing fluid of the hip joint itself.
This fracture occurs between the neck of the femur and a lower bony prominence called the lesser trochanter. This is an attachment point for one of the major muscles of the hip.
This fracture occurs below the lesser trochanter, in a region that is between the lesser trochanter and an area approximately 2 1/2 inches below. In more complicated cases, the amount of breakage of the bone can involve more than one of these zones. This is taken into consideration when surgical repair is considered.
When a hip fracture has been diagnosed, the patient's overall medical condition will be reviewed.
Stable Impacted Fracture
Certain fractures that have not moved ("displaced") may not require surgery.
Because there is some risk that these "stable" fractures may instead prove unstable and displace (change position), periodic X-rays of the area are required.
The surgeon's decision as to how to best fix a fracture will be based on the area of the hip that is affected.
Using metal alloys, high-grade plastics, and polymeric materials, orthopaedic surgeons can replace a painful, dysfunctional joint with a highly functional, long-lasting prosthesis.
Over recent years, there have been many advances in the design, construction, and implantation of artificial hip joints, resulting in a high percentage of successful long-term outcomes.
Cemented total hip replacement
A patient with a cemented total hip replacement can put full weight on the limb and walk without support almost immediately after surgery, resulting in a faster rehabilitation. Although cemented implants have a long and distinguished track record of success, they are not suitable in all instances.
Cemented fixation relies on a stable interface between the prosthesis and the cement and a solid mechanical bond between the cement and the bone. The bond between cement and bone is generally very durable and reliable.
Cemented total hip replacement is more commonly recommended for older patients, for patients with conditions such as rheumatoid arthritis, and for younger patients with compromised health or poor bone quality and density.
These patients are less likely to put stresses on the cement that could lead to fatigue fractures.
Cementless total hip replacement
In the 1980s, new implant designs were introduced, which attach directly to bone without the use of cement. Most are textured or have a surface coating around much of the implant to promote 'natural bonding' with the bone.
Cementless implants require a longer healing time than cemented replacements.
The pelvis is prepared using a process similar to that used in a cemented total hip replacement procedure. The intimate contact between the component and bone is crucial to permit bonding.
Patients with large cementless stems may also experience mild thigh pain.
Cementless total hip replacement is most often recommended for younger, more active patients and patients with good bone quality where bone ingrowth into the components can be predictably achieved. Individuals with juvenile inflammatory arthritis may also be candidates, even though the disease may restrict their activities.
Partial hip replacement
If only one part of the joint is damaged or diseased, a partial hip replacement may be recommended. In most instances, only the head of the femur is replaced, using components similar to those used in a total hip replacement.
The most common form of partial hip replacement is called a bipolar prosthesis.