Partial hip replacement surgery is an orthopedic procedure to replace the top of the femur, also known as the femoral head. The new, synthetic femoral head rests in the patient’s own hip socket. Partial hip replacement, or hip hemiarthroplasty, is less involved than total hip arthroplasty. In patients who need surgery, partial hip replacement substantially reduces hip pain and improves function — patients are also very satisfied with the procedure.

Your hip is essentially a ball-and-socket type of joint, with the head of the leg bone (femur) fitting into a part of your pelvis called the acetabulum. While a total hip replacement involves replacement of the femur’s head and the acetabulum’s surface, a partial hip replacement is replacement of the femur’s head only. This leaves the natural tissues composing the pelvis intact. Also called a hemiarthroplasty, a partial hip replacement is almost always indicated following a traumatic hip injury, such a fractured or broken hip. However, your partial hip replacement surgeon in NYC will typically not recommend this kind of hip replacement procedure if you suffer from degenerative arthritis of the hip joint.

What Are Some Reasons for Partial Hip Replacement Surgery?

A partial hip replacement surgeon will perform this procedure if hip pain is limited to a problem in the femoral head or “ball” of the “ball-and-socket” hip joint. While a total hip replacement is appropriate for almost every cause of hip pain that leads to dysfunction, partial hip replacement surgery is reserved for only certain types of hip pain. The most common reason for partial hip replacement surgery is to treat a fracture in the femoral head (the top of the thighbone is broken). Since it is impossible to “cast” the hip joint like you would a broken arm or broken leg, the only choices are to use a metal pin to hold the bone in place or to replace the femoral head entirely. Almost all patients do better with partial hip replacement than they do with fixation or “pinning.”

A partial hip replacement surgeon may perform the procedure in patients with avascular necrosis or osteonecrosis of the femoral head, although this is less common than it once was. These conditions are usually treated with total hip replacement instead. Infrequently, patients who already have had a total hip replacement but simply need the artificial “ball” replaced may undergo partial hip replacement surgery.

What Are the Differences Between Total and Partial Hip Replacement Surgery?

The main difference between total and partial hip replacement surgery is the amount of joint that is replaced. In total hip replacement surgery, both the “ball” and the “socket” are replaced. In partial hip replacement surgery, only the “ball” or femoral head is replaced. The physical therapy and recovery times are similar in both procedures.

When Is Partial Hip Replacement Surgery Recommended?

A partial hip replacement doctor usually recommends partial hip replacement surgery only in specific circumstances and for specific patients. The surgery is usually reserved for people who have a fracture of the femoral head. In addition, the fracture must be severe.

Specifically, partial hip replacement is reserved for what are called Type 4 femoral head fractures, in which the fractured bones are no longer touching one another. Moreover, simply having a type 4 femoral head fracture is not enough for a hip replacement surgeon to recommend this procedure. Having a metal ball joint rub against a natural hip socket can wear away the joint substance and cause joint degeneration over time. Therefore, partial hip replacement surgery is typically recommended in older and less active individuals with type 4 femoral head fractures who are sedentary or only moderately active in their normal lives.

Hip Fractures

The hip is a common area to sustain fracture, especially under conditions of osteoporosis. The patterns of fracture are typically femoral neck, intertrochanteric and subtrochanteric. Fractures of the femoral neck that are minimally displaced and intertrochanteric/subtrochanteric fractures can be treated by surgical repair through placement of fracture implants that will hold the fragment of bone together rigidly in a reduced position and will allow for immediate mobilization, and in most cases weight bearing without restrictions. This is an important concept and a critical goal to achieve especially in the elderly, since bed rest for even seemingly short periods of time can cause permanent debilitation and can lead to other life-threatening complication such as decubitus ulcers (bed sores) and venous thrombosis (blood clots). In cases of femoral neck fracture in the elderly where the fracture is substantially displaced, a partial or total hip replacement is recommended due to the high risk of a failure of healing when surgical repair is attempted.

Grades of Fractures in Hip Joint Injuries

Grades one, two and three (subtrochanteric, intertrochanteric and fractured neck) will not interfere with the hip joint and can usually be repaired with nailing devices or pins. A grade four fracture (subcapital fracture) is further sub-graded into four other fracture types, according to the severity of displacement occurring at the fracture site.

• Type 1 — A stable fracture with impaction (bones remain pressed together)
• Type 2 — A complete, non-displaced fracture (bones stay aligned)
• Type 3 — A displaced fracture (with two contacting bone fragments)
• Type 4 — A completely displaced fracture (no contact between fractured bone fragments)

If your partial hip joint surgeon in Jersey City diagnoses a type four fracture, this means there is disruption of blood flow to the femoral head that could lead to bone death. Since this type of fracture is unlikely to heal using pins, a partial hip replacement is recommended to prevent a potential total hip replacement in the future. If you have not been diagnosed with a degenerative hip disease like osteoarthritis, you may be eligible for a partial hip replacement.